A "nonpartisan, non profit 'consumer advocate' for voters that aims to reduce the level of deception and confusion in U.S. politics." They "monitor the factual accuracy of what is said by major U.S. Political players in the form of TV ads, debates, speeches, interviews, and news releases.
A sister site which "provides resources designed to help viewers recognize flaws in arguments in general and political ads in particular. Video resources point out deception and incivility in political rhetoric."
Another stellar, non-partisan, not-for-profit site and organization that charges itself with researching and providing information about candidate biographies, voting records, interest group ratings, public statements, campaign finances, and stance on the important issues, which is summarized in the site's "Political Courage Tests" asking the candidates what items or issues they would support if elected.
General hoaxes, news stories, religion, etc. Reasoning is usually explained and sources are cited.