Originally Posted by johnny_d

I know that Google does not like networks of sites (20, 50, 100), they just wont let them rank. If the sites share the same Analytics code, this is a good way for them to find out. The same goes for the Webmaster Tools.

I also heard about people getting all of their sites penalized (for some black hat seo on just one of them), just because of the fact they were sharing the same Google Analytics account (not the same code).

I guess I am talking more about networks of sites. 50, 100 websites or more. I know that Google penalized networks of blogs a while ago too.

On the other hand it is kind of hard, if not impossible to hide a network like that. I am obviously not going to be getting a sepearate hosting for sets of 3-5 sites (out of 50 in the network) etc...