CSpace is a minimal IM with zero server intelligence. It only uses a DHT to find out where people are. After that the application has to do everything peer to peer. This brings up a lot of limitations.
- Without a server, you don't get to have a concept like the UNI, which handles things for you no matter if you are online or not. No leaving messages and such. The DHT normally points directly to your current IP which may break anytime if it's a dial-up.
- Security issue: If you're no longer friends with someone, how can you stop her from finding out your IP number and attacking your computer? Only by changing your identity with everyone else! Or by changing the behaviour of the DHT servers to forward requests to you rather than answer them at anybody's wish, but apparently that's not how the DHT used by CSpace works.
- Server-based applications like large multi-user chats aren't possible. Doing them the distributed way is a challenge (see PSYC2).
- You can't just take part in it using an old IRC or telnet client, you need that specific new software.
- Also DHT is not a generic solution that lets you start from nowhere. A DHT needs to know some servers to start off from, which will tell you which servers you should register with and which servers know about your friends.
- Also CSpace is so happy about end-to-end encryption, but end-to-end is something you can do between any chat client of any chat system, as long as the clients agree on the same format.
- The Remote Desktop feature is kinky, but any client could have done that, too.
- In fact, it's not true that CSpace is serverless: CSpace has a centralistic hidden server in charge of mapping the cspace-id to the actual public key of a person. If that server disappears, you can no longer use your cspace-id, and if that server is corrupted, somebody can steal new friends from you and lead them into talking to somebody else.
- http://cspace.in is a sort of IM system based on DHT
- http://cspace.in/trac/wiki/Suggestions (see Offline Messages to be done as uselessly as Skype did them)