I came onto this scene around 2007, and it was always proper etiquette to reply to an ad, "email sent", and then do so. First to post "email sent" got first dibs. If a deal didn't happen, the second to post "email sent" got a shot, and so on. But once the FAQ changed to the new format, and PM became a feature, this evolution to PM'ing directly, without the publicly accountable "email sent", became the norm and I hated it. It sucks because there is no public accounting of the responses. It made everyone turn suspect and things felt shady.
I never understood how we the people let that happen. I guess sellers could accept higher bids in private, maybe. I don't know.
But it sure ruined the symmetry of selling parts on this site. It really did.
There was always a "Car Guy" honor system in place. Even if offered more, the seller sold to the first in. Seems folks have gotten greedy with this new found valuation of the 2002, and it has ruined the fun on a lot of levels..