I've recently run into a number of innovative sites and products that use Openfire.
!http://www.igniterealtime.org/blog/wp-content/uploads/2007/04/imified.gif![IMifi ed|http://www.imified.com/] provides tools like task management, reminders and todo's through IM bots on AIM, MSN, and XMPP/GTalk. They've just released an API that will make it easy to write bots that work across all major IM networks. Openfire powers their XMPP back-end.
!http://www.igniterealtime.org/blog/wp-content/uploads/2007/04/mosoto.gif![Mosoto |http://www.mosoto.com/] is a real-time collaboration application for Facebook that includes chat along with file and music sharing. They're one of the premier implementors of the Facebook API and have a slick Flash client UI. The service is now in Alpha, but should mature and grow quickly (especially given the size of the Facebook userbase). They use both Openfire and the XIFF Flash API.
!http://www.igniterealtime.org/blog/wp-content/uploads/2007/04/justintv.gif!Final ly, we were told at the Web 2.0 conference that the chat feature on Justin.tv is powered by Openfire. I haven't had a chance to to verify that yet, but if true, it's cool that we're part of such an interesting social experiment. If you haven't seen the site yet, Justin wears a portable camera 24x7 that streams a live video feed to the website. I personally can't imagine broadcasting my life, but I have to respect the social commentary. In a world where we're always connected and available through cellphones and IM, this guy is really always connected and available... to the entire world.
These three examples are part of a broader trend: I think that XMPP will become a critical piece of infrastructure for a large number of next-generation web efforts, including Google. Recent protocol advances like BOSH (XMPP for web pages), Jingle (voice and video) and PEP (advanced presence features) will only further help drive adoption.