It's an interesting idea, and the originator's put a lot of hard work into it, but I think your .sig sums up my opinion of its usefulness. I also can think of lots of concepts that it'd be darn hard to query for without knowing enough regex not to need the site's help. ;-]

I'm also concerned with copyright issues, as it is clearly exploiting an author's code for commercial gain. If he was able to talk Amazon into adding it to their website, I'd think it'd have a better chance of making it. As it is, it's been out a year and not generated any real buzz.