From Rap Genius:

Rap Genius is your guide to the meaning of rap lyrics (basically the internet version of the nerd-ass “rap dictionary” dorm-mate you had in college).

You can listen to songs, read their lyrics, and click the lines that interest you for pop-up explanations – we have thousands of canonical rap songs explained (2Pac, Notorious B.I.G., Jay-Z – even the beginning of the Torah..)

Our aim is not to translate rap into “nerdspeak”, but rather to critique rap as poetry

Who writes the explanations?

Anyone can create an account and start explaining rap. Highlight any line to explain it yourself, suggest changes to existing explanations, and put up your favorite new songs.

If you make good contributions you’ll earn Rap IQ™, and if you spit true knowledge, eventually you’ll be able to edit anything on the site.. just like a hip-hop Wikipedia..

A hip-hop Wikipedia?

Here’s the “Rap Genius Family Tree”:

Source: About | Rap Genius