The reason is that most forums have opt for no follow policy they put nofollow link in your signature due to this google robot is not able to read it and they are not counted by google.

If you want to build backlinks try these things.

1) Directory Submission

2) Blog Commenting on do follow blogs

3) Participate in do follow forums, though they are few but you will find them.

Try and search for forums that do not no follow links, also search and use for dofollow directory and blogs.

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Travelling & Tourism | PC Video Games | Cell Phone Technology PDA

I'll help you a bit. Submit your site to my directory (see signature), it will cost you a dollar but I reckon you'll survive the set-back (grin)! That's one good, juicy link to begin with. Then, usually within one or two hours, an automatic mechanism comes to life that posts your entry to the related Bucklinker Backlinks Blog, where you will have another good and juicy link. Not only that, but it's on a different IP address, in fact directory and blog are hosted with different companies.

Then you have the option to post comments on the above mentioned blog. Via a clever little plug-in I removed the nofollow tags from the comments, so all links you post in/with your comments are dofollow.

And that's not even all! While pottering about on the blog or the directory, follow the link there to the Bucklinker Article Directory and post an article there, putting (of course!) your link(s) in the authors box. Again one or more good juicy links, and again on a different IP address/hosting company!

Oh dear... and all that for just ONE buck (wide grin)!

Be well!

Jaap Verduijn.