We've all read the standard "comment on blogs", "post of forums", "submit to directories" and "write and submit to article directories" as the standard link building mechanisms to use. These are all very effective. I've found that you can expand the "comment on blogs" concept much more if you search out and find the online version of many print magazines that allow comments. Sometimes you find some gems that allow comments with relevant anchor tags that are do follow. It may take some time to find such online magazines, but I've been successful in finding many locations that allow you to comment on articles, include relevant anchors and obtain a free dofollow backlink. Some of the sites providing some links to a few of my clients are coming from PR8, PR7 and PR6 authority sites, with the links coming from PR6 and PR5 comments. Here's where I reveal such a magazine that allows such backlinks with relevant anchor text related to the search marketing industry. Enjoy the free links.