I've added Eva Mendes site to my signature and it fell from approx #34 to #60. It's currently inching its way back up to #56. So far, a negative result for me. Link dropping works well when the anchor text is aligned with post title and topic. Signature links with the same anchor text tend to magnify the results. Some forums consider link dropping as sp*m but on some forums a little self promotion is allowed for memebers that have contributed.
The site in my sig has dropped like a brick since I put it in my sig. It's now on page #13. Before it was on page #3.
Probably because you got thousands of backlinks overnight and it looks spammy. Give it time. Someone put a link to my site in a signature after I was banned (combined it with their gamblings ite) to try and get even with me. So I had thousands of backlinks from this site together with their gambling site. It penalized me for a while, but now my results are better than ever so it had no effect (maybe even a positive effect for all I know).
I've been thinking along the same lines as well. The site is now at #93 so that's a 3 page improvement.
You were penalised probably because the forum is not directly related to your topic. Webmaster related sites tend to do well with backlinks from DP.
I like that idea, but I guess most of forums would carry url as showthread.php..... the same applies to DP. It can be considered as a unique url. Unlike blogs, there's a lot of blog carry it url as what you have mentioned.
With my number of posts the signature links work well. I think that with bogart site the problems are caused by missing WP blog, but... As soon as I reach 9000 posts I will post again. [so far promised help for Eva]
It seems that most forums now won't allow you to put a link in your sig anyway. This one excluded of course.
I don't believe a wp blog would help to much. I'll let it go to the end of the month and see what happens. Then I'll start adding links slow and steady. I've changed the anchor text to 'Eva Mendes' for 'Eva Mendes Fan site' perhaps that will make a difference. More than possible that a spam or seo filter was tripped.
I'm pretty sure (if not already mentioned) that a page needs some sort of PageRank value to add value to a link, therefore if a forum topic only has low PageRank, you would not get much value from a link, only direct visitors.
It is hard to expect the common sense from a bot, but the links from forum are outgoing from one place only.I would expect G just to ignore the rest of the links and give it the value of one link only. The completely different situation is, when all these links are going from different sites.