Do Links In Forum Post turn Nofollow? and is it Bad if not?

[vish.seo]

Nofllow attribute ....
Google has made it clear by adding the nofollow attribute to links in a blog or website will help that site stay in good hands ... now my question is what about links inside a forum post?? does that rule apply??/ meaning how would you turn links in forum post nofollow???

I have a Massage forum Ive added nofollow links only in the news letters ... but in the postings the links are do follow is this okay or not .... any help lol

[Jenie0109]

Forum Posting is by posting regularly to these forums and properly utilizing the signature tags, you can generate much needed back links to your web page which helps with search engine optimization for your site.