
Public Relations is the domain where the experts in relations with other humans are going to brag about, to get money or even votes (being an election year every politician is considering his public relations and his votes). In the online world, harnessing the synergy between Public Relations (that's were PR comes from) and Search Engine Optimization (SEO is its abbreviation) can significantly elevate your online presence and boost brand visibility.
When you are writing the content on your website or blog you should think you are writing for getting more friends among people you have never met before. You won't get them all but you may get many of them depending of your subject and how you are writing about it.