Two thoughts came together today. In the emergent democracy discussions, there have been suggestions for easy internet polling, with the ability to accumulate poll results between sites via links. Thus on your website you could advocate or oppose a poll that someone else has initiated, and distinguish votes cast from your page from overall votes.
This made me think about the Raging Cow controversy, where milk drink marketers exploited bloggers' tendency to rabidly discuss anything weblog related, and link to their website, driving the drink Google's rankings.
Combining these ideas, how about some extensions to the 'a href' tag to say "I'm linking to this, but I disagree with it" and maybe "I'm linking to this but don't count the link as a vote". Google and other link spiders could note these distinctions, and distinguish between popularity, notoriety and ubiquity.
There is also a lot more scope for deriving a personalised search this way - excluding what Cory calls 'left-handed whuffie' and returning search results from places you are likely to agree or disagree with, as well as showing more nuanced rankings.
This is a higher-level way to not feed the trolls.