Personnaly, I'd like to build some KM-system for a restricted circle of colleagues. I'll try to explain :
- create a folders classification that suit your KM needs, maybe using semantic theories, and RDF implementations
- building a FireFox extension that allows to "custom-bookmark" an URL. When a user "custom-bookmarks" an URL, the web-page is screened, "read" and indexed inside Alfresco. Regarding to the content of the web page you "custom-bookmarked", Alfresco would store it in different folders, following your RDF implementation.
- Then you can use the power of Alfresco and Lucene to search for a keyword and get the bookmarks you made, you can be warned (by mail) when another user has just bookmarked a web page containing some keywords are really relevant for you etc …
Further specific developments could be added in order to tune this KM-system