Blog comment, article submission and forum posting are 3 major link building methods I have been using. There are some free advertising forums that allow unlimited dofollow links, and I have been using them to improve my keywords ranking, because by doing these I can increase backlinks without spamming other forums. I find that they are no longer as effective as the beginning(though they still works). Is there anybody else using them too? Any good resources to share? thanks in advance...