"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.
bidirectional XMPP gateway to the Twitter microblogging platform
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.