Now that I look back on the incident I think Nico was texting... This happens all the time to me when I'm on the freeway and the other driver seems to either be on their phone or texting.
Maybe he took a page from one of the Nascar boys and was tweeting while racing: http://sports.yahoo.com/nascar/news?slug=jp-passan_brad_keselowski_twitter_022812
I just remember the move that Alonso did on Vettel in Monza recently - Vettel overtook Alonso with 2 wheels on the grass on Curva Grande. I guess they all do it.