klark0 - 7:16 pm on Aug 18, 2012 (gmt 0)
So what could these "other signals" be ? Almost certainly, they've incorporated excessive anchor text in the first two versions.
I'm thinking they might look at your ratio of nofollow/dofollow links as normal websites don't have more than 5-10% nofollow, while aggressive SEOs tend to have 10%+.
Maybe they'll single out links from popular sources of manipulative links - ie. article directories, web2s, etc. ?