Hello all, I work on an open source social meta-web and annotation tool called ShiftSpace (http://www.shiftspace.org, http://github.com/ShiftSpace/shiftspace/tree/master). The ShiftSpace platform is primarily written in MooTools, however with the release of MooTools 1.2.3, it is now possible for MooTools and jQuery to coexist. To see the kinds of social applications that can be built with ShiftSpace check out http://moma.org.
At the moment the non-GreaseMonkey plugin version of ShiftSpace works just fine running MooTools and jQuery together. However we're looking for people who are avid jQuery+GreaseMonkey hackers who might be interested in the effort to make the GM version of ShiftSpace run both libraries seamlessly. Please check out our website for more info and/or join the discussion at the http://groups.google.com/group/ShiftSpace-dev. If you have any thoughts, feedback or would like to contribute please don't hesitate to contact us. Thanks, David Nolen (Lead ShiftSpace Developer)
