Making Backlinks from web 2.0 destinations is another sort of SEO. Most Search Engine Optimization specialists have been using Web 2.0 locales are Tier 1 backlinks, essentially in light of the way that they acknowledge Google likes setting backlinks. Some examples of web 2.0 include Blogs, social networking, wikis, or web applications.
Web 2.0 websites include the following techniques and features like anchor links, tags, authoring, extensions, search, and signals. And with using web 2.0 sites webmasters can improve SEO and build high pr quality backlinks.
So, here is List of Dofollow Web 2.0 Sites
25+ High DA Social Bookmarking Sites List Referenced for SEO