the other major trend is that both search and social distribution have substantially eroded eBay's original network effect as a destination for buyers & sellers... now both search (via SEM) and social (via FB & other networks) are also able to acquire & influence buyers.
anyway, i probably rag on eBay a little too much since i used to work there (via PayPal), but they have slowed down on the innovation quite a bit. that used to be offset by them buying innovative services, but that has also slowed down in recent years.