If I were to define "good thick content" in a way that a robot could understand, I might look at the following variables:
- High wordcount, let's say maybe 1,000 words or more
- At least 1 relevant image on the page
- Bonus points if it's an original image (i.e. not a stock photo)
- High ratio of words to links out
- Lots of social shares
Going with that profile, it's possible that ask.com etc. were the intended targets and Metafilter was collateral damage.
This is all speculation so take it with a grain of salt.