hi dear web masters i wan to know about the do follow and no follow links? can any body tell me? /////////////////////////////////////////////////////////////
Dofollow simply means giving PR(page rank) to the site that is linked to your site while Nofollow command does not allow PR to be passed to a certain page or site. Hope it answers your question. if you would like a detailed explanation you can search it at the web. Goodluck!
http://en.wikipedia.org/wiki/Nofollow Basically, if a link to your website has the "rel=nofollow" attribute, it will not be counted as a true backlink and therefor google will not value it when placing your website in its search rankings.
having backlinks from dofollow sites will help increase your site's ranking in serp provided that you use your targeted keywords as your forum sigs.
Something to note as well is that different search engines deal differently with nofollow. Google will not even let the spider crawl links that have the nofollow attribute. But it will crawl the link if it is found elsewhere. Whereas ask.com completely disregards the nofollow attribute indexing and weighting dofollow and nofollow links alike. This might be quite a good post for further reading: http://www.searchenginejournal.com/how-google-yahoo-askcom-treat-the-no-follow-link-attribute/4801/
By my understanding Google DOES follow nofollow links, it's just that they do not apply any PR to the link once followed.