I think with all the clampdown on using web2.0 as pbns, you should literally invest into good proxies that are near virgin status or at least not shared by anyone else - using an abused IP would get your account locked/blocked once created, thus it would be wasted effort.
Apparently, there are a certain subnet range that the web2.0 has banned due to excessive botting behavior coming from those subnet, thus, it would be better to ensure to use only near-virgin dedicated IPs.