I think you're right about that. Prosper can clearly see the writing on the wall that their claim to be the largest player in the field is just months away from vaporizing, so it's time to attempt to re-frame a new definition that will allow them to continue to suggest their own relevancy.
I wonder if anyone has access to the actual number of users who have ever posted a listing or actually placed a bid on a loan?
Then, I'd be curious to know how many people fit that description within each calendar year since the inception. That would be an interesting graph.