eBay will no longer accept American Express cards over 'unacceptably high' fees
theverge.com
theverge.com
Which means they still accept Amex, but through places that one would imagine add their own processing costs on top of the fees they've negotiated with Amex.
It'd be really curious to see the costs involved here.
I agree about PayPal, but they charge their own fees and abstract the source of the money away completely. Presumably they have a better deal with Amex