With so much work still to be done on UserQuotes, this is really premature, but..
Since the main thing that the UserQuotes service does is allows a GROUP of people to collect, maintain, and annotate a collection of references to web pages, complete with thumbnails and complete archives of the web page, we have wondered if people might any ideas for ways we could repurpose the code to serve other functions -- like a social/group bookmarking tool, etc?