There's a lot of seemingly inaccurate and conflicting information about penguin which makes it hard to know what's best to do. I note that Matt Cutts says
If you have been hanging out in a lot of blackhat forums, trading different types of spamming package tips and that sort of stuff, then this might be a more eventful summer for you
But I'm guessing most people here (like myself) have done nothing of the sort, but perhaps (also like me) have some dubious incoming links from very old link exchanges and directory submissions, and others they don't know where they came from.
So it's clearly both inaccurate and rather insulting to say that penguin 2 only applies if we 'have been hanging out in a lot of blackhat forums, trading different types of spamming package tips'.
Also the whole question of whether it is an actual penalty or just a new ranking with more of the dubious links ignored is not clear - but this makes a big difference to what approach is best (if they are now just excluding lots more links then why bother disavowing them or trying to get them removed)
Lastly, reports of a genuine and full recovery from penguin are few and far between to say the least - are there a few actual documented cases where sites have definitely recovered from penguin, and whether this was due to removing poor quality links etc?
I'd like to be sure this is something I have a chance of successfully tackling before I start wielding the hatchet...if the whole thing is really just deeply flawed (as I suspect when I look at sites in our niche that have been penalised) or has a completely different goal for google than what they are saying (eg brand promotion or ad promotion) then it's probably not worth doing anything to try and sort it out.