Just like OneSocialWeb, buddycloud started out using XMPP's built in event stream. We found that this quickly ran out of steam for scaling and was too constrained to build a really good social system. So we pivoted and the new channel servers that are being built are all independent from particular XMPP server implementations.

The channel approach runs as a separate server instead of trying to build everything into existing XMPP servers. Decoupling the channel server release cycle (almost daily) from the longer release cycle of XMPP servers speeds development.