We all know that the biggest factor that propels any webpage to appear on the top of the SERPs is link building and the quality of links pointing to the same webpage you are trying to rank a keyword for. With this in mind, the first step we usually do is to do the basic - get a few links from social bookmarking sites, directory submissions, blog business reviews, blog comments and forum links.
But what most of us have come disregard is the fact that free classifieds were one of today's most loved pages by the searh engines, We've seen how Craigslist, Kiiji, olx and more come to life in almost any long tail keywords as well as major keywords today. For sure they can't be just some coincidence.
Here in the Philippines, for example, what webmasters have observed is the use of free classifieds in trying to rank a webpage to the top of the SERPs success however is measured in terms of promotions that you will do with the Ad page that you made.
Imagine having a link in there and getting on top of the search for multiple keywords including the long tail ones that never even know you can rank for? I have done it myself and I know that this one works. This is actually not just a form of SEO but more on search engine marketing or SEM.