I'm making my first sets of web 2.0s and I cant help wonder why Google would let them gain extra weight from being pages/subdomains of Tumblr and WordPress etc. Is Google very aware that web 2.0 are one of the blackhat Seo techniques? To fight blackhat stuff, wouldn't it be a good idea for Google to simply ignore any web 2.0's domain authority? Since a mysite.wordpress.com dosen't really have much to do with wordpress the company domain? Also are there any web 2.0s that actually do well on their own? It seems like something people use to try making a website out, but never get serious with. If it had good content or authority they would upgrade the domain. (Another reason why i don't understand google gives them link weight like real sites) Sorry if there is something obvious I'm missing, just trying to understand web 2.0s and Google more.