same:
- they both use UDP and act very… torrent like.
- they can distribute data (i2p with tahoe lafs and freenet by default can do this)
- they can circumvent firewalls up to a point
- they DO NOT make you anonymous when going to google.com
- they can use DHT to more or less find other peers/routers
different:
- Freenet can work inside of i2p but not the other way around.
- Freenet can be a friend-to-friend darknet while i2p like to use w.e. IPs are also running i2p
- they have different attack vectors (IDK specifics, pls post if you want)
- freenet has forums built in and updated from time to time. I2P has Sydney but needs to be patched/replaced.
- freenet will distribute site contents; I2P, or eepsites, still are centralized
- freenet needs to you dedicate hard drive space and bandwidth. I2P only needs bandwdith.
- IMO I2P has more potential than freenet