Based upon the SearchMonkey platform, Yahoo users can now enhance their searches with developer-created apps.

The enhancements (there were 39 available as of 1:00 pm EDT today) available in Search Gallery highlight specific sites in results such as public domain book text from Feedbooks, Last.fm song and artist information, and Yahoo Local data.

Under the "Customize" tag in the Yahoo search window, the user can add any of these applications to tailor their search results.

Apps that users will find installed by default upon signup are Yahoo Video ("Discover new content for your media-hungry mind! Watch music videos, news, sports, comedy, movie previews and more - right from your search page"), Yahoo Travel ("Looking for place to stay when you travel? The Hotel Infobar application shows you detailed hotel ratings, pictures, price ranges and more so you can find the best hotel for your next trip), and Flickr ("Flickr loves Search! View fun, interesting photos from other Yahoo! users for image-related queries.")

Unfortunately, the whole thing works best in theory so far. After I added enhancements from Amazon.com, eHow, Feedbooks, and Last.fm, all of my search results were unchanged. It wasn't until I added the Stumbleupon infobar that my results window was visibly affected.

By typing in "Curtis Mayfield," I intended to see what information about the famous R&B songwriter would turn up in Yahoo's results. The 100 pages of results I was provided carried with them the Stumbleupon ratings bar which puts user-supplied ratings and reviews under search results. Granted, only a single result from the 100 pages actually had a user review, but it was the first enhancement I tried that provided an unmistakable result every time (even if that result was the "Enhancement failed" notice).