Social Bookmarking
To expand on the idea of personal bookmarking above, it would be interesting to have a del.icio.us style of bookmarking; social bookmarking. A way to identify which posts are the most beneficial/favorite throughout the community. I don’t see this being used as a vanity thing, but rather a ‘solutions promoter’. Not every solution is going to get posted on UnifyCommunity.
You could see which topics are the most popular. Outside of Showcase, this popular topics are going to be problems and solutions. GUIManager, UISprite, SmartFox, Pathfinding, etc.
FAQ
Ideally, it needs to evolve into a better run FAQ. I know the search option is there, but we all know it’s not used as often as it should be. Most posts are one-line questions, concerning one feature/function. I don’t have an easy solution for this aside from “build an FAQ manually.” However, once built and stickied, it really should cut down on the number of repeat posts.
Unsolved/Solved Status
This feature is on some Q&A sites/forums, and it could work here in the same way that you can flag a post with a Poll. Basically the post would be tagged as “Open” or “Solved.”
Solved posts would let someone know that the original post question had a solution as a response, which is nice. Sometimes I start reading a topic only to realize no one ended up solving the issue.
Open posts would let someone know that the problem is unsolved. You could even browse by “Open/Unsolved” in an attempt to answer questions/problems, and not get distracted by gossip/showcase-type posts.
There are a lot of things which could be done, but I think the most effective ones will be those which target the one-line question/problem posts, and assist those people getting those problems answered (by Unity staff, or by the community). An easier way to identify/sort those will result in more answers, and more solutions available for all.