Not really, is safe.

Is not like your login IP for particular Web 2.0 is assigned forever to that account so you can't log in from other IP.

Very few if any web20 sites log people's IP or match what IP you log in with each time. When IP and email become an issue is when you try to sign up with multiple accounts under the same IP. Lots of peoples IP change for one reason or another.

If you are going the web 2.0 route (which is quickly becoming inefficient) then use FCS Networker and do tiers with GSA. The end.

I've noticed "Super web2.0s" ranking the best, which are multi-page web2.0s that mimick the look and feel of the original website.

As far as unique IPs go when logging in, you do not need to worry about this if you have less than a few per website (personal use / small network). However, if you are building for clients or own a larger network you need to use proxies otherwise the web2.0s are more likely to ban your IP and sites if the see abuse of any kind.

Private proxies are necessary to use many accounts from same site like of Social and Web 2.0s