What's the point of a revolution without general copulation?

I'm so happy with this episode. Everybody lived and the Doctor danced.

I guess River remembered the Doctor for the same reason that the Doctor remembered Rory after he got erased from history. She's a time traveler, too and got almost as special a relationship with time as he. In Flesh and Stone she argues with him about who of them should sacrifice themselves and jump into the crack as the Angels demanded.