Hi Mohammed,
Quick answer, the "rel=nofollow" tag is not attached currently to profile links or signature links. In other words, it is "DoFollow".
If you want to know if a website has that tag on links you can use the Firefox addon called "NoDoFollow". If you do a search for "NoDoFollow" the first result should lead you to the Mozilla addon page where you can install it. (For free of course.)
Another favorite of mine is something called SeoQuake. It's a free addon that will put a line through NoFollow links (if you tell it to) but it also will tell you a LOT more about a web page. (How old it is, how many backlinks, how many pages are indexed, Alexa rank and so on...)
BUT, please stay current on the GDI Forum rules before posting any links anywhere.
Hope this helps.
Vincent Parker