Inspired by MeatBall:ScottMoonen's post on the focus of a PersonalLogServer on friendships rather than on projects. A ProjectLogServer is like a personal log server, except that it focuses on a single project rather than a single person.
A concrete example. The WikiGateway software implements a draft version of the Atom protocol. Related to his development of this software, the developer (BayleShanks) made some comments on Sam Ruby's blog about how Atom should interact with wiki. Bayle also made some comments on AtomWiki. These posts were of course related to the WikiGateway project, and so it would be nice if they appeared somehow on the main wiki for that project (InterWikiSoftware's wiki).
If the WikiGateway project had a ProjectLogServer, then when someone in the project posted something relevant elsewhere on the web, this would be reported to the project's log server, which would then compile a list of recent changes related to the project from all over the web.
This permits a project to essentially transcend a single wiki (e.g. discussion relevant to implementing the Atom protocol in WikiGateway spans both AtomWiki and InterWikiSoftware's wiki). This feature is complementary to UnifiedClusters.
I think it would be easiest for individuals to direct their software to just send everything to a PersonalLogServer, and then to have the PersonalLogServer repost relevant items to the ProjectLogServers which the individual is involved in.