This has been repeatedly suggested, and something was tried, but it's too difficult to moderate. Texcoco suggested a chat format he used on his blog, and I think I remember one of the moderators suggested that people who want to chat go there.
Anyway, something was tried and I think the failure to play nice by some posters ended the experiment.
Those that say, don't know. Those that know, don't say.
I've visited a number of "chat rooms" and note that they sometimes get populated by people who (1) post poorly thought out comments (pendejadas), (2) "ego" trip "sword-play" comments between posters, (3) demeaning scat talk (4) or all of the above.
For now, I vote NOT to have a BB chat room on the basis of my concerns as well as the added costs of monitoring said chat room.