diff --git a/src/lib/forum/relevance.test.ts b/src/lib/forum/relevance.test.ts
new file mode 100644
index 0000000..5f89371
--- /dev/null
+++ b/src/lib/forum/relevance.test.ts
@@ -0,0 +1,141 @@
+import { RelevanceCalculator } from './relevance';
+import { Post, Comment, Cell, User } from '@/types';
+import { MessageType, VoteMessage } from '@/lib/waku/types';
+import { expect, describe, beforeEach, it } from 'vitest';
+import { UserVerificationStatus } from './types';
+
+describe('RelevanceCalculator', () => {
+  let calculator: RelevanceCalculator;
+  let mockUserVerificationStatus: UserVerificationStatus;
+
+  beforeEach(() => {
+    calculator = new RelevanceCalculator();
+    mockUserVerificationStatus = {
+      'user1': { isVerified: true, hasENS: true, hasOrdinal: false },
+      'user2': { isVerified: false, hasENS: false, hasOrdinal: false },
+      'user3': { isVerified: true, hasENS: false, hasOrdinal: true }
+    };
+  });
+
+  describe('calculatePostScore', () => {
+    it('should calculate base score for a new post', () => {
+      const post: Post = {
+        id: '1',
+        cellId: 'cell1',
+        authorAddress: 'user2',
+        title: 'Test Post',
+        content: 'Test content',
+        timestamp: Date.now(),
+        upvotes: [],
+        downvotes: []
+      };
+
+      const result = calculator.calculatePostScore(post, [], [], mockUserVerificationStatus);
+      
+      expect(result.score).toBeGreaterThan(0);
+      expect(result.details.baseScore).toBe(10);
+      expect(result.details.isVerified).toBe(false);
+    });
+
+    it('should apply verification bonus for verified author', () => {
+      const post: Post = {
+        id: '1',
+        cellId: 'cell1',
+        authorAddress: 'user1',
+        title: 'Test Post',
+        content: 'Test content',
+        timestamp: Date.now(),
+        upvotes: [],
+        downvotes: []
+      };
+
+      const result = calculator.calculatePostScore(post, [], [], mockUserVerificationStatus);
+      
+      expect(result.details.isVerified).toBe(true);
+      expect(result.details.authorVerificationBonus).toBeGreaterThan(0);
+    });
+
+    it('should apply moderation penalty', () => {
+      const post: Post = {
+        id: '1',
+        cellId: 'cell1',
+        authorAddress: 'user2',
+        title: 'Test Post',
+        content: 'Test content',
+        timestamp: Date.now(),
+        upvotes: [],
+        downvotes: [],
+        moderated: true
+      };
+
+      const result = calculator.calculatePostScore(post, [], [], mockUserVerificationStatus);
+      
+      expect(result.details.isModerated).toBe(true);
+      expect(result.details.moderationPenalty).toBe(0.5);
+    });
+
+    it('should calculate engagement bonuses', () => {
+      const post: Post = {
+        id: '1',
+        cellId: 'cell1',
+        authorAddress: 'user2',
+        title: 'Test Post',
+        content: 'Test content',
+        timestamp: Date.now(),
+        upvotes: [],
+        downvotes: []
+      };
+
+      const votes: VoteMessage[] = [
+        { id: 'vote1', targetId: '1', value: 1, author: 'user1', timestamp: Date.now(), type: MessageType.VOTE },
+        { id: 'vote2', targetId: '1', value: 1, author: 'user3', timestamp: Date.now(), type: MessageType.VOTE }
+      ];
+
+      const comments: Comment[] = [
+        { id: 'comment1', postId: '1', authorAddress: 'user1', content: 'Test comment', timestamp: Date.now(), upvotes: [], downvotes: [] }
+      ];
+
+      const result = calculator.calculatePostScore(post, votes, comments, mockUserVerificationStatus);
+      
+      expect(result.details.upvotes).toBe(2);
+      expect(result.details.comments).toBe(1);
+      expect(result.details.verifiedUpvotes).toBe(2);
+      expect(result.details.verifiedCommenters).toBe(1);
+    });
+  });
+
+  describe('timeDecay', () => {
+    it('should apply time decay to older posts', () => {
+      const now = Date.now();
+      const oneDayAgo = now - (24 * 60 * 60 * 1000);
+      const oneWeekAgo = now - (7 * 24 * 60 * 60 * 1000);
+
+      const recentPost: Post = {
+        id: '1',
+        cellId: 'cell1',
+        authorAddress: 'user2',
+        title: 'Recent Post',
+        content: 'Recent content',
+        timestamp: now,
+        upvotes: [],
+        downvotes: []
+      };
+
+      const oldPost: Post = {
+        id: '2',
+        cellId: 'cell1',
+        authorAddress: 'user2',
+        title: 'Old Post',
+        content: 'Old content',
+        timestamp: oneWeekAgo,
+        upvotes: [],
+        downvotes: []
+      };
+
+      const recentResult = calculator.calculatePostScore(recentPost, [], [], mockUserVerificationStatus);
+      const oldResult = calculator.calculatePostScore(oldPost, [], [], mockUserVerificationStatus);
+
+      expect(recentResult.score).toBeGreaterThan(oldResult.score);
+    });
+  });
+});
diff --git a/src/lib/forum/relevance.ts b/src/lib/forum/relevance.ts
new file mode 100644
index 0000000..037bb54
--- /dev/null
+++ b/src/lib/forum/relevance.ts
@@ -0,0 +1,330 @@
+import { Post, Comment, Cell, User } from '@/types';
+import { VoteMessage } from '@/lib/waku/types';
+import { RelevanceScoreDetails, UserVerificationStatus } from './types';
+
+export class RelevanceCalculator {
+  private static readonly BASE_SCORES = {
+    POST: 10,
+    COMMENT: 5,
+    CELL: 15
+  };
+  
+  private static readonly ENGAGEMENT_SCORES = {
+    UPVOTE: 1,
+    COMMENT: 0.5
+  };
+  
+  private static readonly VERIFICATION_BONUS = 1.25; // 25% increase
+  private static readonly VERIFIED_UPVOTE_BONUS = 0.1;
+  private static readonly VERIFIED_COMMENTER_BONUS = 0.05;
+  
+  private static readonly DECAY_RATE = 0.1; // λ = 0.1
+  private static readonly MODERATION_PENALTY = 0.5; // 50% reduction
+
+  /**
+   * Calculate relevance score for a post
+   */
+  calculatePostScore(
+    post: Post,
+    votes: VoteMessage[],
+    comments: Comment[],
+    userVerificationStatus: UserVerificationStatus
+  ): { score: number; details: RelevanceScoreDetails } {
+    let score = this.applyBaseScore('POST');
+    const baseScore = score;
+
+    const upvotes = votes.filter(vote => vote.value === 1);
+    const engagementScore = this.applyEngagementScore(upvotes, comments);
+    score += engagementScore;
+
+    const { bonus: authorVerificationBonus, isVerified } = this.applyAuthorVerificationBonus(
+      score, 
+      post.authorAddress, 
+      userVerificationStatus
+    );
+    score += authorVerificationBonus;
+
+    const { bonus: verifiedUpvoteBonus, verifiedUpvotes } = this.applyVerifiedUpvoteBonus(
+      upvotes, 
+      userVerificationStatus
+    );
+    score += verifiedUpvoteBonus;
+
+    const { bonus: verifiedCommenterBonus, verifiedCommenters } = this.applyVerifiedCommenterBonus(
+      comments, 
+      userVerificationStatus
+    );
+    score += verifiedCommenterBonus;
+
+    const { decayedScore, multiplier: timeDecayMultiplier, daysOld } = this.applyTimeDecay(score, post.timestamp);
+    score = decayedScore;
+
+    const { penalizedScore, penalty: moderationPenalty } = this.applyModerationPenalty(score, post.moderated || false);
+    score = penalizedScore;
+
+    const finalScore = Math.max(0, score); // Ensure non-negative score
+
+    return {
+      score: finalScore,
+      details: {
+        baseScore,
+        engagementScore,
+        authorVerificationBonus,
+        verifiedUpvoteBonus,
+        verifiedCommenterBonus,
+        timeDecayMultiplier,
+        moderationPenalty,
+        finalScore,
+        isVerified,
+        upvotes: upvotes.length,
+        comments: comments.length,
+        verifiedUpvotes,
+        verifiedCommenters,
+        daysOld,
+        isModerated: post.moderated || false
+      }
+    };
+  }
+
+  /**
+   * Calculate relevance score for a comment
+   */
+  calculateCommentScore(
+    comment: Comment,
+    votes: VoteMessage[],
+    userVerificationStatus: UserVerificationStatus
+  ): { score: number; details: RelevanceScoreDetails } {
+    // Apply base score
+    let score = this.applyBaseScore('COMMENT');
+    const baseScore = score;
+
+    const upvotes = votes.filter(vote => vote.value === 1);
+    const engagementScore = this.applyEngagementScore(upvotes, []);
+    score += engagementScore;
+
+    const { bonus: authorVerificationBonus, isVerified } = this.applyAuthorVerificationBonus(
+      score, 
+      comment.authorAddress, 
+      userVerificationStatus
+    );
+    score += authorVerificationBonus;
+
+    const { bonus: verifiedUpvoteBonus, verifiedUpvotes } = this.applyVerifiedUpvoteBonus(
+      upvotes, 
+      userVerificationStatus
+    );
+    score += verifiedUpvoteBonus;
+
+    const { decayedScore, multiplier: timeDecayMultiplier, daysOld } = this.applyTimeDecay(score, comment.timestamp);
+    score = decayedScore;
+
+    const { penalizedScore, penalty: moderationPenalty } = this.applyModerationPenalty(score, comment.moderated || false);
+    score = penalizedScore;
+
+    const finalScore = Math.max(0, score); // Ensure non-negative score
+
+    return {
+      score: finalScore,
+      details: {
+        baseScore,
+        engagementScore,
+        authorVerificationBonus,
+        verifiedUpvoteBonus,
+        verifiedCommenterBonus: 0, // Comments don't have commenters
+        timeDecayMultiplier,
+        moderationPenalty,
+        finalScore,
+        isVerified,
+        upvotes: upvotes.length,
+        comments: 0, // Comments don't have comments
+        verifiedUpvotes,
+        verifiedCommenters: 0,
+        daysOld,
+        isModerated: comment.moderated || false
+      }
+    };
+  }
+
+  /**
+   * Calculate relevance score for a cell
+   */
+  calculateCellScore(
+    cell: Cell,
+    posts: Post[],
+    userVerificationStatus: UserVerificationStatus
+  ): { score: number; details: RelevanceScoreDetails } {
+    // Apply base score
+    let score = this.applyBaseScore('CELL');
+    const baseScore = score;
+
+    // Calculate cell-specific engagement
+    const cellPosts = posts.filter(post => post.cellId === cell.id);
+    const totalUpvotes = cellPosts.reduce((sum, post) => {
+      return sum + (post.upvotes?.length || 0);
+    }, 0);
+    
+    const activityScore = cellPosts.length * RelevanceCalculator.ENGAGEMENT_SCORES.COMMENT;
+    const engagementBonus = totalUpvotes * 0.1; // Small bonus for cell activity
+    const engagementScore = activityScore + engagementBonus;
+    score += engagementScore;
+
+    const mostRecentPost = cellPosts.reduce((latest, post) => {
+      return post.timestamp > latest.timestamp ? post : latest;
+    }, { timestamp: Date.now() });
+    const { decayedScore, multiplier: timeDecayMultiplier, daysOld } = this.applyTimeDecay(score, mostRecentPost.timestamp);
+    score = decayedScore;
+
+    const finalScore = Math.max(0, score); // Ensure non-negative score
+
+    return {
+      score: finalScore,
+      details: {
+        baseScore,
+        engagementScore,
+        authorVerificationBonus: 0, // Cells don't have authors in the same way
+        verifiedUpvoteBonus: 0,
+        verifiedCommenterBonus: 0,
+        timeDecayMultiplier,
+        moderationPenalty: 1, // Cells aren't moderated
+        finalScore,
+        isVerified: false, // Cells don't have verification status
+        upvotes: totalUpvotes,
+        comments: cellPosts.length,
+        verifiedUpvotes: 0,
+        verifiedCommenters: 0,
+        daysOld,
+        isModerated: false
+      }
+    };
+  }
+
+
+
+  /**
+   * Check if a user is verified (has ENS or ordinal ownership)
+   */
+  isUserVerified(user: User): boolean {
+    return !!(user.ensOwnership || user.ordinalOwnership);
+  }
+
+  /**
+   * Build user verification status map from users array
+   */
+  buildUserVerificationStatus(users: User[]): UserVerificationStatus {
+    const status: UserVerificationStatus = {};
+    
+    users.forEach(user => {
+      status[user.address] = {
+        isVerified: this.isUserVerified(user),
+        hasENS: !!user.ensOwnership,
+        hasOrdinal: !!user.ordinalOwnership
+      };
+    });
+    
+    return status;
+  }
+
+    /**
+   * Apply base score to the current score
+   */
+    private applyBaseScore(type: 'POST' | 'COMMENT' | 'CELL'): number {
+        return RelevanceCalculator.BASE_SCORES[type];
+      }
+    
+      /**
+       * Apply engagement score based on upvotes and comments
+       */
+      private applyEngagementScore(
+        upvotes: VoteMessage[], 
+        comments: Comment[] = []
+      ): number {
+        const upvoteScore = upvotes.length * RelevanceCalculator.ENGAGEMENT_SCORES.UPVOTE;
+        const commentScore = comments.length * RelevanceCalculator.ENGAGEMENT_SCORES.COMMENT;
+        return upvoteScore + commentScore;
+      }
+    
+      /**
+       * Apply author verification bonus
+       */
+      private applyAuthorVerificationBonus(
+        score: number,
+        authorAddress: string,
+        userVerificationStatus: UserVerificationStatus
+      ): { bonus: number; isVerified: boolean } {
+        const authorStatus = userVerificationStatus[authorAddress];
+        const isVerified = authorStatus?.isVerified || false;
+        
+        if (isVerified) {
+          const bonus = score * (RelevanceCalculator.VERIFICATION_BONUS - 1);
+          return { bonus, isVerified };
+        }
+        
+        return { bonus: 0, isVerified };
+      }
+    
+      /**
+       * Apply verified upvote bonus
+       */
+      private applyVerifiedUpvoteBonus(
+        upvotes: VoteMessage[],
+        userVerificationStatus: UserVerificationStatus
+      ): { bonus: number; verifiedUpvotes: number } {
+        const verifiedUpvotes = upvotes.filter(vote => {
+          const voterStatus = userVerificationStatus[vote.author];
+          return voterStatus?.isVerified;
+        });
+        
+        const bonus = verifiedUpvotes.length * RelevanceCalculator.VERIFIED_UPVOTE_BONUS;
+        return { bonus, verifiedUpvotes: verifiedUpvotes.length };
+      }
+    
+      /**
+       * Apply verified commenter bonus
+       */
+      private applyVerifiedCommenterBonus(
+        comments: Comment[],
+        userVerificationStatus: UserVerificationStatus
+      ): { bonus: number; verifiedCommenters: number } {
+        const verifiedCommenters = new Set<string>();
+        
+        comments.forEach(comment => {
+          const commenterStatus = userVerificationStatus[comment.authorAddress];
+          if (commenterStatus?.isVerified) {
+            verifiedCommenters.add(comment.authorAddress);
+          }
+        });
+        
+        const bonus = verifiedCommenters.size * RelevanceCalculator.VERIFIED_COMMENTER_BONUS;
+        return { bonus, verifiedCommenters: verifiedCommenters.size };
+      }
+    
+      /**
+       * Apply time decay to a score
+       */
+      private applyTimeDecay(score: number, timestamp: number): { 
+        decayedScore: number; 
+        multiplier: number; 
+        daysOld: number 
+      } {
+        const daysOld = (Date.now() - timestamp) / (1000 * 60 * 60 * 24);
+        const multiplier = Math.exp(-RelevanceCalculator.DECAY_RATE * daysOld);
+        const decayedScore = score * multiplier;
+        
+        return { decayedScore, multiplier, daysOld };
+      }
+    
+      /**
+       * Apply moderation penalty
+       */
+      private applyModerationPenalty(
+        score: number, 
+        isModerated: boolean
+      ): { penalizedScore: number; penalty: number } {
+        if (isModerated) {
+          const penalizedScore = score * RelevanceCalculator.MODERATION_PENALTY;
+          return { penalizedScore, penalty: RelevanceCalculator.MODERATION_PENALTY };
+        }
+        
+        return { penalizedScore: score, penalty: 1 };
+      }
+}