eBay could be taking on the 800-lb. gorilla in the room, Amazon, with its new same-day shipping strategy. Where eBay and bricks-and-mortar stores have generally played second fiddle to Amazon's huge growth story, together they may be a more powerful force and could quickly grow to become a more competitive player in the online retail space. eBay's same-day shipping could be the key to the puzzle. Its partnerships with a few San Francisco bricks-and-mortar retailers allows it to serve an unmet online retail need, without the same inventory management logistics that Amazon has to worry about.

Even despite the headwinds, though, Amazon remains a Foolish favorite, and one of the companies we named in our premium report: "3 Stocks That Will Help You Retire Rich." Click here to keep reading and start down the road of long-term wealth-building.