A lot of these are obsoleted by a good ranking function, which will tend to pull the best hits to the top even without the additional metadata. For example, a search for "rectangular humphrey" turns up this
: "I'm starting to get offers from people who want to sponsor features in my CPAN distro, KinoSearch," which is very relevant -- I didn't realize you were the author of KinoSearch, which you are also suggesting as a platform.
I agree that node ratings, etc., can be useful, but one of Google's big lessons is that quantity can beat quality: intelligent analysis of huge amounts of generic data can beat analysis of specialized data. This is particularly visible in its approach to natural language translation, but is nearly as important in search.