Google PagerankGoogle rank websites and blog by their ranking method called Pagerank. Pagerank is determined by how many backlinks are there to a specific site. The more the backlinks you have, the higher will be your Pagerank. Google considers each backlink as a vote from other Webmaster to you.
Difference Between DoFollow and NoFollowMatt Cutts (currently the head of Google's Webspam team) in 2005 introduced the "nofollow" concept.
There are two ways one can link to your blog, they can either place a Dofollow link or a Nofollow Link. Lets say if a webmaster places a link to your blog with a DoFollow tag then you will get the vote from his/her website and that link would be counted in your pagerank as a backlink to you site. Lets say if a webmaster places a link to your blog with a NoFollow tag then you won't get any vote from his/her website and neither would that link be counted as a Backlink to your site/blog.nofollow is a value that can be assigned to an HTML element to instruct some search engines that a hyperlink should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring.