Web of Trust (service)
Web of Trust is an Internet crowdsourcing service which enables users to rate websites and see the average rating of all others. WOT Services Ltd. is based in Helsinki, Finland, but as an Internet service is available worldwide. This may be the largest community rating system for websites.
How it Works
WOT offers plugins for common browsers, so users may install one of these, and rate this way. When a user visits a website which has been given a poor rating on average, a warning is displayed over the page. Also, when a user searches the web using a poplar search engine, WOT shows the community rating of each result. Alternatively, if one does not want to install the plugin or is unable to do so, they may create an account and rate websites online. However, poorly rated sites will not trigger a warning, and search results are not checked.
This rating system can work quite well, but there is one big problem: the human factor. In theory, a few misinformed people will not result in inaccuracy, but if enough people are misinformed or biased, ratings will become inaccurate. This is especially true for political and religious websites. For example, a review on Alliance Defending Freedom's website comments that much of their site is based on fiction, and the idea of "Planned Parenthood selling fetal tissue [has] no basis in fact." Minority sites such as Conservapedia also receive poor ratings, because the majority of WOT users disagree with the sites' contents.
There is also the risk of fraud. It is difficult to defend against this, so one must hope that any attempt at fraud will be overwhelmed by genuine ratings. However, some sites have been successfully attacked by "farmed" reviews, such as seems to have happened to Conservapedia. This gives the opposition of WOT a good reason to speak poorly of the service.