How often do you end up at a website and wonder if it's safe to download a program there or to enter in an email address? If you already use SiteAdvisor, TrendProtect, or CallingId, you probably already have a good idea which sites are safe. WOT offers a similar protection to you but uses the power of all of it's users to help identify bad web sites.
I've been using WOT side by side with SiteAdvisor and I've gotten comfortable enough with it that I'm dumping SA in favor of WOT. I like the idea that I'm getting advice from fellow web surfers and not from a security company. We're all out there on the front lines and we need to stick together.
Quote from the website
Keep yourself protected from unreliable online vendors, spam, spyware, viruses, phishing and other scams. Unlike traditional security systems, WOT will warn you already before you interact with any suspicious websites. The color coding is like traffic lights: green to go, yellow to slow down and red to stop.
WOT has information on over 16 million websites.
Each community member can contribute. WOT is a democratic system where everyone can participate. You can share your knowledge to help other users surf safer by giving ratings to sites that you have used. The system processes ratings and calculates the reputation for each web site. Eventual attempts to manipulate the reputation data are eliminated by sophisticated algorithms.