Rap Genius is particularly awesome because it kind of started as a legal hack (you can't just publish lyrics directly, due to copyright, but crowdsourced line by line like this is ok), but then turned into something far more useful than the existing (legal, regulated, expensive) alternatives.<p>I mean, they have Nas and others coming on the site as Verified Artists explaining their own songs.<p>$15mm is a lot of money, but it was probably a situation of Rap Genius having enough growth to command a high valuation, and a16z needing a certain percentage to make their investment acceptable to themselves.