Apparently one of the features is that you can use it to easily scrape other websites! The only overhead would be one network API call (the fetching and parsing of information all happens on the Yahoo! servers and it returns the sanitized output to your application). I might give it a spin sometimes :).
I use YQL and Pipes for this Twitter analyzer. I'd be sad to see it go. It's great technology for what it does, but I'm not sure enough people know how to take advantage of it or trust its stability or longevity.