I have tested a lot with web2.0 in the past couple months and I found that most of them dont work. Some of them put the content to noindex / nofollow or block bots via robots.txt Others get indexed and have follow links but for some reason the links dont count. For example I built a couple of wix.com sites. I throwed in links with anchor text = "long anchor text phrase" Usually when you later search for "long anchor text phrase" you then find of course the web20 site because "long anchor text phrase" is part of the content. But you also find your money site because google considers it relevant for "long anchor text phrase" because that is were the link goes to. This is not the case for wix and weebly for example even if the links are indexed for a long time. Long story short: For me I only found wordpress and tumblr to work. The rest was useless. Which web2.0 worked for you?