This specification defines an XMPP protocol extension that enables entities to include RFC822-style address headers within XMPP stanzas in order to specify multiple recipients or sub-addresses.
"XBookmarks" for "XMPP Bookmarks". It is the Firefox implementation of XEP-0048: http://xmpp.org/extensions/xep-0048.html. You simply need a Jabber account and you can use it. Currently it is very basic, though functionnal, as the XEP is.
jabber server2server verbindungen sollen ab 4.1.2009 gültige ssl-cert benutzen
tweet.IM is a free service offered by ProcessOne. It enables you to use micro-blogging platforms like Twitter from your existing instant messaging application. The service makes it easier for you to send messages (called tweets), as well as follow the tweets of other users.