It's time to bid on a birthday cake -- eBay.com is celebrating its 10th anniversary.
The wildly popular Internet auction site is of the few Internet companies that got a huge market share, kept it, and profited. Industry analysts estimate one out of every $4 spent on the Internet is spent on eBay.
For a growing number of people, it has become a way of life. Among the crush of eBay devotees gathered for this week's annual user convention in San Jose, Calif., are people who have sold millions of dollars worth of merchandise through the Internet garage sale.
Steve Rubenfaer of San Francisco, who is known as a "titanium-level power seller," has sold more than $150,000 a month in collectible stamps.
"We'll probably sell about three or four million [dollars] on eBay alone this year," he said.
EBay has changed businesses and lives. Amy Morsini makes about $2,400 a month by selling baby clothes out of her Oakland Hills, Calif., home. She is raising twin sons.
"It gives me the freedom of not having to go back into the corporate world," she said.
EBay says it has 430,000 members who make all or part of their living by selling over the network. By comparison, that's the equivalent of everyone who lives in the cities of Atlanta or Sacramento, Calif.
But with so much success, eBay is under attack from other Internet companies like Amazon and Google, which now feature auctions and third-party sales. EBay has to invent new sales gimmicks and keep users happy.
They know any business on the Internet can quickly go from top dog to also-ran.
Company legend says eBay started as a way for collectors of Pez candy dispensers to find each other.
EBay now sells every product imaginable. Used cars comprise 30 percent of sales, and even a $2 million house in Newport, R.I., is up for auction on the site.
"The one that was quite amazing to me was the highest-priced item that has ever sold on the site, which was a $4.9 million business jet," said eBay Chief Executive Officer Meg Whitman.
The oddest item: a grilled cheese sandwich that seemed to show an image of the Virgin Mary, which fetched $28,000 at auction.
ABC News' Brian Rooney filed this report for "World News Tonight."