Their main product being Google's search engine, of course.
I've noticed that Google's giving better results than about 6 months ago, when I started using Yahoo search for the most part. Google had been overrun by SEOs and it was annoying me. Now Google's search index is updated much more often than the competition, especially Microsoft. I'm not sure if this is their strategy to get rid of search spam, but it seems to be a much more enjoyable experience all around. I see news articles in the main index sooner, and I'm seeing a lot less spam.
Bottom line, it looks like I'm back to using Google for search, though I still like My Yahoo a little bit more than personalized Google.