Code: google.co.uk/support/forum/p/Webmasters/thread?tid=21eacb9726b3ca3c&hl=en If I am to belive what is written above I understand 2 things. If you have a lot of backlinks in a short period of time its a big flag from google and you shouldnt file for a reconsideration report. Plus this penalties expire or something like that. You can read more of this here: Code: Google Webmaster Tools notice of detected unnatural links site:xxx.google.co.uk replace xxx
If a site naturally goes viral or has some huge advertising (like during a big TV event) it could potentially get an enormous amount of links in a short amount of time. Google does not penalize this. The only thing I can conclude is that if your page gets a huge amount of the same kind of links then that triggers a penalty. But even then that doesn't make a lot of sense to me because I've blasted some of my test sites with enormous amounts of the same links like blog comments. They don't drop or even dance.
from what I read further on those blogs is that keyword diversity is more important then link type diversity. Also how unique the content you use is important. people got this kind of warnings and had white hat sites, really black hat sites, big, small, using all kind of types of links. There is no 1 type of backlink that triggers a flag. There are lots of them and we all do them. Solution: keep doing the best seo you can and keep a low profile