Competition has hardly been the only problem. In the middle of last year, eBay was stung by a cyberattack that forced it to tell 145 million users to change their passwords, and a Google algorithm change that pushed down eBay results in search traffic.
None of that has been enough to scare away one of eBay's top investors.
Hamish Douglass, CEO of Australia's Magellan Financial Group, which owns 2.6 percent of the e-commerce site, sees tremendous value in eBay's customer base (now 157 million), its leadership in countries including the U.K., Germany and Korea and the highly profitable marketplace model that comes from not holding inventory.
As for battling Amazon and a host of upstarts, the critical factor for Douglass is that they're all grabbing business from traditional stores, particularly as shopping goes mobile.
"Both eBay and Amazon are taking market share from physical retailers, it's just that Amazon is taking it faster," said Douglass. "They're both winning."
One emerging area where eBay has been particularly quiet is in marketplaces for services. Loads of start-ups have popped up to clean houses, park and drive cars, install complicated electronics and deliver groceries.
Porch in Seattle connects 3.2 million home improvement and maintenance pros with consumers across the country who need specific types of help.
Landscapers, plumbers, electricians and gadget geeks find jobs in their area by signing on with Porch and taking advantage of the site's rapidly growing customer base. Porch also has a deal with Lowe's, so the big box retailer can offer experts for any home improvement gig imaginable.
EBay could choose to forge a similar partnership, said Porch CEO and co-founder Matt Ehrlichman.
"Imagine if you're buying a certain product on eBay that requires installation or assembly," said Ehrlichman, whose company has raised $100 million in the two years since its launch. "That's where product sales coupled with services makes sense for users."
In a statement, an eBay spokesperson said the company has a three-pronged strategy for growth, albeit with very broad mandates.
"EBay will focus on our core customers and build a more robust commerce platform, create a more vibrant marketplace and deliver exceptional product and brand experiences for our 157 million active buyers around the world," the statement said.
To be sure, the company still has plenty going for it. The business is generating so much cash that in January, management announced a $2 billion stock repurchase plan. (The company also announced an additional $1 billion buyback Thursday morning when it reported Q2 net revenue that grew 7 percent to $4.38 billion.)
Even as small merchants like Teman have bailed for rival sites, eBay still ranked fifth on the 2015 EcommerceBytes Sellers Choice list, which factors in qualities like profitability, customer service, ease of use and communication. Ahead of eBay were Etsy, Amazon, Bonanza and Ruby Lane.
Brian Yacktman, a longtime eBay investor, originally bought the stock because of PayPal, but expects to maintain shares of both after the split.
Yacktman, who manages $400 million as chief investment officer of YCG Investments in Austin, Texas, sees an online commerce market growing 15 to 20 percent a year through 2018. Even though eBay won't keep pace with the sector, it remains a big brand in a hot space.
"Yes, eBay will be a share loser, but at least the pie is still growing," Yacktman said. "It's still prevalent in people's minds. People still think of Amazon and eBay along with the niche places, and they may shop between all of them."