Certainly a harsh blow and a lesson learned, but not the lesson you think. The lesson is to not allow a third party "black box" to be the central traffic source for the monetization model of your business. Rapgenius understood this well and does have an excellent community on boarding strategy, but was still heavily reliant on google as a main pillar of its customer acquisition model.
I've lost one Alexa top 2000 site to a google penalty, and several smaller sites, saw this coming miles away.
I know exactly what they are going through, never forget the day when my JV partner called me at 4AM and told me the apocalypse scenario has happened. Even worst than the financial blow of losing a $30k a day advertising property, was the brutal realization of googling your brands name and seeing it not show up. Going in to analytics real time and seeing a sub 100 number for the first time in 6 months was quite an eery feeling as well.
Google did this to set an example, and they will be reinstated worst case in 6 months.