Most forums incorporate "Nofollow" into signature links. So forum signatures usually aren't too beneficial. That said, if you're a helpful poster, you should see a fair amount of traffic to your site from other members clicking your link.
Signature link could gives only a tiny weight. They are very easy to create and have no trust from search engine especially Google. You may rely on signature link if your website competing with very low to none competitive search terms. Otherwise signature link is useless.
Forum signatures have a few factors that you have to consider, like: (a) Are the pages in which your signature is located indexed? (Like if you post in a 90-page topic, only a few of those pages might be indexed and therefore only a few of those linked might be counted.) (b) How many other people have links in their signature that have replied? (Outbound links still apply to forums! ) (c) How relevant is your signature to your website? I want to elaborate on (c) a bit. I mean relevancy could be different in that it's been proven that Google (and most other search engines) value links embedded in paragraphs of relevant text over just a link that's thrown out there. (Ever wonder why spammers have all those keywords they throw in their along with one or two links? It's to change the relevance of the text around them.)
We have to keep in mind that, how much that particular forum page's PR is. Other wise it's like a link from a PR zero. Although the root domain's credibility might add some weight.
Hey, you might want to check out http://www.big-boards.com/ They list the biggest forums in the world. You can order them by member count, traffic amount etc.
Do follow forum gives you more advantage then other way it's give you back link and divert traffic on your site. Posting Related to the your site is more beneficial for your site.
Dofollow forums with high pr could help you the best... and you should take in consideration that forum is relavent to your topics as well (Website Genre)...
Yes forum signature do have a lot of weight as far as link building seo work is concerned and add lots of value to the domain mentioned in the signature of forums and provide us with valuable backlinks for our website. All the high pr dofollow forums are best ones to achieve backlinks.
Absolutely correct, only difference is that their value may be different from other link. Some link may high value and some link may only a few value. Depends on your link quality.
My competitor gets 10K+ backlinks from forum signature and it ranks 2 for a 45K- search keyword. really impressive ,although everyone know it is spamming ,but BigG do not cares,it just counts
No, 100 posts from the same domain name will be better than one post but you will get diminishing returns. 100 posts on different domains will however have a much greater effect, assuming all other factors remain the same.. i.e PR, outbound links, do follow etc.