WOT is a good initiative in identifying malicious websites and suggesting genuine ratings by end users themselves based on their actual as well as factual experience.
Not always accurate, and definitely check out the ENTIRE scorecard not just the one little circle, there can be a number of red warnings about malware hidden behind a rather green circle in a search result :/ such is the nature of a community run tool though I assume, it is democracy...
Still, it's usually a good indicator. And it's an awesome concept. So I am very glad for it. Despite occasional annoyances :D