With SEO getting more time consuming and expensive, have any of you switched to having one site with subdirectories with different topics? I have about 20 developed sites right now and only about half of them make money. I'm thinking of developing all my new sites under one domain and each subdirectory will contain a separate Wordpress install, covering a different topic. Ideally, I wouldn't have to do as much linkbuilding and all links to the main domain would in turn benefit the subdirectories. But with a lot of links to the main domain, it might possibly be hard to rank for some of the more profitable keywords (while maybe ranking for some less popular long tails). If anyone has any input on this method or has gone this route, I am all ears. Do you think the benefits of this method would outweigh any drawbacks?
