I’ve seen so many cases of webmasters nofollowing legitimate external links it is not funny. Any external link on their site is nofollowed, even when quoting text on the other site. IMO, the original purpose of nofollow has long been defeated in specific industries. As more webmasters continue doing everything they can to preserve their pagerank, the effectiveness of nofollow will continue to erode.
By building enormous amounts of value, Facebook and Google both became tremendously successful. They didn't focus on revenues at the outset. They focused on value. And every single blog and business must do the same. While this might run contrary to someone who's short on cash and hoping that internet marketing is going to bring them a windfall overnight, it doesn't quite work that way.
There’s obviously a huge number of reasons why a website might link to another and not all of them fit into the categories above. A good rule of thumb on whether a link is valuable is to consider the quality of referral traffic (visitors that might click on the link to visit your website). If the site won’t send any visitors, or the audience is completely unrelated and irrelevant, then it might not really be a link that’s worth pursuing.
Search engine optimization (SEO) receives a lot of love from inexperienced marketers. It’s seen as “free marketing” in that you can handle your own SEO work (as long as you follow some rules to do so), and thus all it requires is your time to make things happen. SEO is simply what you do to your website and web pages to make them show up in “organic” (or unpaid) search results on search engines.
While ordinary users were not that interested in pages' scores, SEOs of a different caliber felt that this was a great opportunity to make a difference for their customers. This obsession of SEOs with PageRank made everyone feel that this ranking signal is more or less the only important one. In spite of the fact that pages with a lower PR score can beat those with a higher score! What did we receive then, as a result?