Rap Genius has become a staple for hip-hop fans looking to dissect the meanings of popular song lyrics. The site hosts thousands of visitors who can annotate song lyrics with their own qualitative analysis, and it recently added a feature called Rap Stats that lets you graph how often a word or string of words has been used in songs over time.
Rap Stats results often strongly correlate with greater shifts in history and pop culture. For example, peak references to "Obama" occurred, unsurprisingly, in 2008, the year he was first elected president. The inverse relationship between "crunk" and the drug "molly" mirrors molly's rapidly increasing popularity as a party drug over the past few years.
[Image: Flickr user pictureorpictures]