PageRank is a link analysis algorithm, named after Larry Page and used by the Google web search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of “measuring” its relative importance within the set. The algorithm may be applied to any collection of entities with reciprocal quotations and references. The numerical weight that it assigns to any given element E is referred to as the PageRank of E and denoted by PR(E).
Link Building is a important part of Search engine optimization.These backlinks will be able to able to rank your page higher and improve your traffic from search engines.But not any backlinks will help you to rank your page higher.
Backlinks specifically from high PR blogs and forums will be able to get you a high page rank for your blog.Do Follow Blogs and forums encourage you to comment on their site by allowing the do follow attribute on their comment section and hence help you to achieve good high PR backlinks.
So here i have listed out blogs and forums that have Do follow attribute to encourage commenting.Try to be active in these pages as frequently as possible to achieve constant good backlinks.