It's actually using yahoo store builder. pg has no control over it, because yahoo owns it. He mentioned that to me when I reported that the mobile interface broke various parts of his site.

He made this site in the early 2000s using the store builder he coded in the 90s. His framework probably doesn't even have support for SSL (because it was written in the 90s).

This is really a good question, especially for someone who's presenting themself as a programmer.