Thanks for the idea, it would be nice to have that markup work in the announcement subject.
At the moment you can use HTML to add your 'a' tag to make the subject (or part of the subject) linkable.
Thanks for the sugegstion to try HTML, Greg. I still think it would be good to actually provide an optional target url field as part of the announcement object model. There are complications that could arise from putting markup into the Subject field, and I suspect that Announcements very often have a target url for more info. As I look at the current "Plugin Contest" announcement on Jivespace it seems to fit this pattern, and we hit the same situation almost immediately at DZone.
Clearspace users expect to click headlines. It seems to be embedded into the DNA of Clearspace that they should.