Updated IPFS evaluation based on comments

For discussion, see: https://github.com/status-im/dagger-research/pull/5

evaluations/ipfs.md

@@ -1,7 +1,7 @@
 An evaluation of the IPFS paper
 ===============================
 
-2021-01-06 Mark Spanbroek
+2021-01-07 Dagger Team
 
 https://ipfs.io/ipfs/QmR7GSQM93Cx5eAg6a6yRzNde1FQv7uL6X1o4k7zrJa3LX/ipfs.draft3.pdf
 
@@ -17,25 +17,25 @@ Dagger. It is not meant to be a criticism of IPFS.
   (§2.1.2)
 + Uses proof-of-work in S/Kademlia to discourage Sybil attacks (§2.1.3)
 + Favors self-describing values such as multihash (§3.1) and multiaddr (§3.2.1)
-+ BitSwap protocol for exchanging blocks supports multiple strategies (§3.4.2)
++ BitSwap protocol for exchanging blocks supports multiple strategies (§3.4.2),
+  so it should be relatively easy to add a micropayment strategy.
 + Uses content addressing (§3.5)
 + The Merkle DAG is simple, yet allows constucting filesystems,
   key-value stores, databases, messaging system, etc.. (§3.5)
 
 #### Cons:
 
-- Kademlia prefers long-lived nodes, which is not ideal for mobile enviroments
-  (§2.1.1)
-- BitSwap falls just short of introducing a currency with micro payments,
-  necessitating additional work for nodes to find blocks to barter with (§3.4)
-- Merkle DAGs and Paths (§3.5.1) feel like an unnecessary complication at the
-  protocol level; they could have been implemented on top of a system consisting
-  solely of content addressable chunks
+- Kademlia prefers long-lived nodes (§2.1.1), which is not ideal for mobile
+  enviroments (although it's unclear whether there are any better alternatives)
+- The default BitSwap strategy falls just short of introducing a currency with
+  micro payments, necessitating additional work for nodes to find blocks to 
+  barter with (§3.4)
 - Object pinning (§3.5.3) inevitably leads to centralized gateways to IPFS, such
   as Infura and Pinata
-- There are no self-describing multiformats for encryption and signing (§3.5.5)
-- IPFS uses variable size blocks instead of fixed-size chunks (§3.6)
+- There are no self-describing multiformats for encryption and signing (§3.5.5),
+  although [multicodec](https://github.com/multiformats/multicodec/) can
+  probably be used here.
+- IPFS uses variable size blocks instead of fixed-size chunks (§3.6), which
+  might make it a bit harder to add incentives and pricing
 - Supporting version control directly in IPFS feels like an unnecessary
   complication (§3.6.5)
-- Handles mutable state by hacking it into the routing DHT (§3.7.1), instead of
-  using a separate mutable naming system like ENS