It is ebay hands down. Ebay made millions of profit for many different people, people live off of ebay, people make careers out of ebay, people can buy things that they could never find before,etc. how does yahoo compete with that? While yahoo is a contender. We could still figure things out without. I think yahoo/google had the biggest impact on the internet itself. Think of it. You already know all the websites for places you know of in real life(enterprise rental,airlines,hotels,retail stores,etc.)