Why have the chat clients been switching back and forth?
The chat was switched to Mibbit, a client of IRC, to ensure everyone could chat with whomever they wanted, but Mibbit crashed for an extended period of time, so the client was switched back to Meebo. Also, the chat will potentially be switched back to IRC in the future, but only after Charles can code it into his own server or find a more reliable client with which to connect. To quell worries about a future “super fast” chat, like the Mibbit experiment, do not worry, as the chat may be split up according to location, i.e.: people in Pallet Town will be in the Pallet Chat, people on Route 1 in the Route 1 chat, etc.