A friend and I built the whole eBay + Pinterest mashup earlier this year (http://rumma.ge). We were trying to solve the "browsing" problem that eBay has. Basically, if you have a specific product you're searching for, the traditional search interface did an OK job. But if you're just browsing through "vintage transistor radios" or art or any visual category, it was difficult to browse.

These new changes are great because one of eBay's long-hidden assets is it's product images. It hosts more unique product photos than pretty much any other company out there and for a long time, it surfaced those product images as 140px x 140px thumbnails. Focusing on showing larger, higher-quality images is going to be a big win for users.

That being said, I don't have much confidence in their feed setup. eBay is trying to create an entirely new browsing behavior and while it will definitely result in new sales (how could it not over the old homepage?), the mashup up of a users varied interests into one feed is incredibly disorienting. I just loaded up a couple of interests (biking, guitars, and baseball) and I'm seeing a hodgepodge of handbar grips, random baseball cards, and really nice Les Pauls. While the format seems nice, the content isn't really there yet--and the content, i.e. the quality and relevancy of listings surfaced isn't going to be carried by the format alone.