How do you crush eBay (NASDAQ:EBAY)? The question has become mostly rhetorical at this point. You just can't topple the world's leading online auctioneer. If the dot-com magnets such as Yahoo! (NASDAQ:YHOO) and Amazon (NASDAQ:AMZN) tried with their own clones and failed to draw much of an audience despite offering significantly lower fees, then are you really going to give anyone else much of a fighting chance?

As tantalizing as it may seem to have a heavy such as Microsoft (NASDAQ:MSFT) or Google (NASDAQ:GOOG) hypothetically force its way in for a slice, it's probably not going to work. eBay's rivals couldn't catch up when eBay was much smaller, and the tall order to challenge eBay grows stilts with every passing quarter.

Indeed. Last month, the prolific Motley Fool Stock Advisor newsletter recommendation saw its second-quarter profits double while revenues shot up by 52%. So if you want to kick eBay when it's down, my best advice would be to buy a ladder.

But that doesn't mean that companies aren't carving a niche around the eBay premise of exchanging goods and services online. These players can survive -- and even thrive -- if they specialize. One of our sponsors,, bases its trading platform on users buying and selling available stock from one another -- without the market makers in the middle. While eBay has domain names and websites for sale, it's not likely to match the popularity of the dot-com monikers being peddled on Afternic. You can argue that when it comes to secondhand books, eBay just doesn't stand a chance against Amazon's massive collection of used editions.

However, some companies have taken the eBay model one step further. Instead of exchanging money for merchandise, they have reintroduced the long-lost art of bartering. That's what is doing with its service where users get to swap old CDs, DVDs, and video games for someone else's old CDs, DVDs, and video games. What are you willing to offer for one of Google's beefy Gmail accounts? The unaffiliated Gmailswap site is all ears. While many sites that promote bartering such as TradeAway seem to be populated with members that will ultimately go for a cash transaction, wouldn't it be great if eBay found a way to cash in on currency beyond legal tender?

Sure, it would make for an awkward bidding process. Granted, trust and fraud fears will escalate when two items are being crisscrossed around the country. But eBay has the garage sale market right there in its grubby little hands. It has stocked shelves worldwide collecting dust in many of its members' eBay Stores. While one can argue that eBay is better off cashing in on two separate monetary transactions -- especially since its acquisition of PayPal -- there seems to be a fragmented market out there ripe for eBay's picking.

I told you I'd marry you, eBay. I meant it. But, I'm just curious now. Exactly what is in that dowry I keep hearing so much about?

Do you think entering the barter market would be a mistake for eBay? If you were CEO Meg Whitman where would you go to grow eBay further? All this and more in the eBay discussion board. Only on

Longtime Fool contributor Rick Munarriz has been an eBay member since the 1990s. However, he does not own shares in any of the companies mentioned in this story.