whatson - 9:56 pm on Sep 17, 2011 (gmt 0)

Didn't they have (or have) 1000s of quality checkers, but they were all volunteers? I recall this maybe a few years ago, but can't find anything mentioned about it.

It almost certainly checks how users interact with the pages.

I don't think you can say this, what do you have to support it? There are some seriously bad sites out there, that have not been affected at all.