It was user-based....there was no need for labs input really, as the Network and Web Shields covered Avast!'s input already....maybe if it was a stand-alone, but as a bundle only, it would have been pretty redundant, unnecessarily so.
Now it has a Phishing filter.....I'm not sure if the filter is run by Avast! or if they are using someone else's list like Phishtank or Googles. So it is not totally user-based now. But it is not "scanning ahead of you" or anything like that.
As far as rating abuse goes.....if you look, all it asks you is "do you like this site and how much?" Very ambiguous, it almost takes rating abuse out of the picture, since all it does is take an opinion poll of Avast!'s users. And everyone is entitled to their opinion regardless of intelligence. The tags (porn, warez, etc.) could be abused, but the colored slider? Its an opinion score, no more or less. Everyone is entitled to their opinion regardless of intelligence.