Re: Why IMAP and not XNMP?
"What eBay and Amazon provide cannot be decentralized. They succeed BY being middlemen: a moderator/facilitator in this case. They reduce the "caveat emptor" risks. Plus Amazon is itself a retailer: no middlemen in those cases."
I used Google to find stuff on Amazon, even though Amazon has a search function.
Break down the functions. Product catalog management, reputation management, sales process mediation, escrow, insurance, payment handling, and other stuff. These functions can be provided a la carte. What Amazon and eBay do is bundle it for our convenience, which admittedly is a value provided as well. We like convenience, sometimes to our own detriment. It needn't be centralized, or i.e. monopolized. As protocols mature and interoperability advances, we can have a different world. I'm not betting on it, but I don't give up hope.