A friend of mine at eBay told me that they are constantly trying to buy out their competition. Anytime a small online auction site makes a splash, eBay is there to buy them out, effectively playing whack-a-mole. They go to great lengths to ensure that not only are they the 'king of the hill', but that they have the only hill. Their business model is not particularly novel or complex. It is extremely vulnerable to competition. They fully realize this. Hence they attempt to buy out competitors before they can gain enough momentum. Just look through the list of acquisitions they've made over the years (and this list is not comprehensive. I know there are several more smaller acquisitions that aren't even listed here). They buy out other auction sites just so they can either shut them down or prevent them from growing into greater threats in the future. It is almost certainly the most important factor in keeping them in the position they're still in today. This is eBay's modus operandi. If they see you as competition, they will try to squash you or acquire you.
https://en.wikipedia.org/wiki/List_o...itions_by_eBay