I find Google's actions to be bizarre.
Getting people to link to you is what SEO is all about. Basically every site concerned with SEO does it in one form or another -- I thought this was what most every blog affiliate program was about!
So Google decides to "punish" RapGenius just because its program got a little bit of public notice, while 99.9% of other sites which do the same, continue doing the same thing, unpunished?
It just comes across as capricious and petty. For a site as large as Google, there should be some kind of due process involved with clear published guidelines, or (preferably) they should just work on improving their algorithm.
How is what Rap Genius is doing any different than Amazon or iTunes paying you for affiliate links, or you paying a blog to advertise you, or buying a friend a beer to include a link to you? Where exactly does the line get drawn?