The best place on the internet to start researching the NFL's history is the league's own website, which includes an extensive collection of historical material, including a chronological overview of key events in the league's past, profiles of legendary players, histories of each of the 32 teams, and comprehensive statistics, standings, and records dating all the way back to 1920.

The TV commercials that air during the Super Bowl's timeouts are now almost as popular as the game itself. The name of the website says it all—this is the place to go for all things big-game-ad-related.

The website design may be rudimentary, but Lloyd Vance's BQB site—the "BQB" stands for "black quarterback"—offers the most comprehensive and best sourced history of African Americans' experience playing the most important and scrutinized position in sports: NFL quarterback.

Owned by ESPN, the Undefeated aims to discuss "the intersections of race, sports and culture." This awesome page on race in the NFL does just that.