Cassandra stable build was relased 2nd January 2013, and I think IPB will follow by this, but I dont know if this is good choice to use cassandra on every public forums. Is cassandra provided only to pages like Twitter of Facebook? I dont know if it would be good decision to attepmpt to use cass in future for small pages. Can some1 say if cassandra would be good choice for page with following stats?
The IPB forum is 8 years old.
With a site profile like that, you're probably better off with MySQL or some equivalent. If you want more of a document or KV store, you could also take a look at some of the other technologies, like MongoDB or Couchbase. They are a bit easier to learn and operate than Cassandra and will certainly handle your load.