1. Web 2.0 sites 2. blog commenting 3. Articles 4. Social bookmarking Do a DP search and you're bound to get a lot of threads on this
I use the same list : squidoo.com/dofollow it is really nice for everything including article, press release, social bookmarking, social networking etc. It helps to get backlink.
you can search by dofollow social bookmarking sites, dofollow blogs for commenting, dofollow articles list etc. and can do valuable submissions.
You'll get lots of useful advice on this site looking at the threads, but if you really want to succeed, you need to create something that will actually capture the imagination of key players in your field. rather than mindlessly adding blog comments, why not brainstorm something you could create - a picture, an article, a video, a song, a story that you think is cool, and you think other people in your tribe will think is cool.
You can get dofollow link by dofollow forum posting, blog commenting on do follow blog, bookmark on do follow social bookmarking site
2. blog commenting - very few blogs are dofollow 4. Social bookmarking - biggest social bookmarking sites are nofollow
Here are some places where you can get free do-follow links. Blogger.com This is one of the top blogging sites online today, and thus it carries a good deal of weight on search engine results. Get a free blogger account and post on your blog regularly. Post only quality content and include links to your site at the end of each post, using target keywords on the link. Squidoo.com Set up a single page at squidoo.com and include as many do-follow links as you can. But keep in mind that over linking will hurt you. The best strategy is to have a much larger ratio of quality content than links. Wordpress.com Wordpress is probably the most SEO blog site today. You should build a few blogs and keep them updated. Wordpress’s wide variety of widgets and tagging options make it a perfect place to gain do-follow links. w3schools.com W3schools.com is a great place to learn html, if you’re willing to take the time. You can build pages and post them in a similar fashion as squidoo. Linkmarket.com This is a site where other websites looking to exchange links can connect with each other and help each other out. Linkmarket is free to use and makes the process of exchanging do follow links easy. FreeTrafficSystem.com This is probably one of the lesser-known places to get links, but it’s a good one. It requires that you possess a little bit more computer skills than other sites, but if you’re willing to learn it’s worth it. Article sites The following article websites carry a good deal of weight with search engines, and posting successful articles on these can boost your rankings and get you a lot of do-follow links: Ezinearticles.com, articlebase.com, goarticles.com and isnare.com. Blog comments Blog comments are yet another place to get backlinks. To ensure that your comment gets accepted, read the full post and write a relevant blog comment before you insert any links to your site. Forums Forums posts, because they’re not tightly regulated, do not carry as much weight as blogs, but they’re still a great place to expand your online reach. Press releases The rules for optimizing press releases differ from the rules of optimizing content pages and blog posts. The ideal frequency of keywords, for example, is different for press releases. A good site to learn how to write good press releases is prwebdirect.com.
You can go with blog commenting to get Quality back link. Don't spam on blogs while doing comment posting on it. Also Posting forum with signature to your site, you can use social networking and Social Bookmark that's the great to get traffic to your site also increase Google PR. Good luck.
I remember that there has an software tool to find the nofellow blogs and forums, you can search it on google.