The cofounder's tacky annotations were apparently the last straw.
Despite the big, outlandish rap-bro caricatures its three founders put forward, Rap Genius envisions itself the "Talmud for the Internet," the foremost annotation platform of Western civilization. And aside from bombing Google with spammy search engine tactics (for which the service was swiftly punished) the Rap Genius guys have mostly managed to avoid negative press lately--which, all things considered, is a good thing for a company looking to one day become a serious knowledge resource to rival the likes of Wikipedia.