You already knew that TechNet launched enhanced search with Live Search.
Search is an interesting tool, and reveals while writing this that my blog of Feb 19, 2008 on this was ripped verbatim by this splog.
TechNet enhanced search offers refinements, such as by topic and by source (show below) that let you filter out lots of content that you are not interested in, so that you can more easily find the content you want. For example, the search shown below shows that there are blog and forum posts, KBs, and even an Edge video available in the top results for RSAT. But, what I really want is the "official" content in the technical library.
Clicking on the "Documentation & Articles" refinement pops Server Manager Technical Overview Appendix to the top of the results in .9 seconds. Now, this content was in the original list of 20000 items, but is was "below the fold" and hard to detect amongst the other content.
IT Pros need content fast. TechNet enhanced search refinements helps get them there. The new "Documentation & Articles" source refinement is a big productivity booster if you suspect that the content you want is in the library.