The lack of persistence built into the protocol (and thus clients) is a big problem for team communications. You can have a bot log your channel, but they'll often have holes creep into the logs somehow, and for private discussions require yet one more access control system.
Having a web irc client that provided a common backlog and search for all users, instead of requiring things like znc to make that usable, would be great. The private part is fraught though.
