My company recently started using HipChat and I really like it. I expected to prefer IRC because of the standard, open protocol and the choice of clients, but the HipChat application works much more smoothly on my Linux desktop than any IRC client I've tried, and it's been adopted more widely across my organization than IRC ever was - making it much more useful, even if that really just comes down to marketing it to…
That's HipChat 2.1.1013 running on x64 in Vmware 10.0.2 w/ 8gb of a total of 32gb allocated. Oh yea, I'm doing nothing in HipChat, just idling in a single channel, with two inactive conversations with AFK people open. The chat window contains no animated GIFs or Youtube vids or anything wild either.
I've been strongly considering switching to using a regular XMPP client especially since feature creep seems to be be bringing features I don't want (video chat etc)
Edit: I should add the view is filtered, the CPU load + memory usage in the top is from an encrypted filesystem backup currently running