Here are some screenshots from a site that I had penalised:
The site was created on 21st April 2012.
I then used high PR links with targeted anchor text (though EVERY anchor was different but all were keywords).
With these links I targeted mainly two pages, but did point a few at a third page. The fourth page was completely unlinked.
Graph 1 shows all pages.
Graph 2 shows page 1 that I targeted heavily (traffic dropped to 0)
Graph 3 shows page 2 that I targeted heavily (traffic dropped to 0)
Graph 4 shows page 3 that I didn't target as heavily, but still targeted. (traffic almost to 0)
Graph 5 shows page 4 that I didn't target at all. (traffic at about 25%)
Graph 6 shows the recovery.
Penalty - Imgur
I did not change the content on the site, nor remove any of the links as I wanted to see what would happen to the site.
Page 1 and 2 that I targeted heavily have not returned with good rankings, whereas page 3 and 4 have completely recovered.
I say recovered, I didn't deserve to rank before and I don't deserve to now (for page 3 at least as I did target that with bought links).
I would love to hear people's thoughts on why this was penalised in this way.
I need to emphasise that the only links that have ever been pointing at this site were these bought links and a link from the Twitter profile.
Basically, the links (or site?) got penalised, but they were certainly not PERMANENTLY discounted as the site has returned.