I seldom use Yahoo, but a set of HITs requiring a lot of Yahoo searches made me realize just how badly-identified their text ads are. They really blend in with the real results without excessive scrutiny. So I modified my original CH Google Color-Coded Results
script to work on Yahoo search results ads. Update: now also supports other special types of Yahoo results beyond ads.
See also: my MTG thread post
For many more MTurk-related userscripts, see the Turking Scripts set