Several of the early prizes went to organizations, the prize makes no distinction between organizations and individuals. Also, several of the individuals who got the prize have been given it because of their position/work for an organization(like Liu Xiaobo who got it for charter 08).

The time of the nomination for Obama's peace prize is a hangup rooted, unfortunately, in ignorance of how the comittee works. It's not your actions prior to the nomination that's important, it's your actions after the nomination, right up until today.

And yes, Obama got his prize for his commitment to diplomacy, or in other words, on the same grounds Liu Xiaobo got his.