Use for data analysis

eBay is a publicly visible market which has attracted interest from economists, who have used it to analyze aspects of buying and selling behavior, auction formats, etc., comparing them with previous theoretical and empirical findings.

Computer information systems researchers have also shown interest in eBay. Michael Goul, Chairman of the Computer Information Systems department of the W. P. Carey School of Business at Arizona State University, published an academic case based on eBay's big data management and use in which he discusses how eBay is a data-driven company that processes 50 petabytes of data a day.

eBay uses a system that allows different departments in the company to check out data from their data mart into sandboxes for analysis. According to Goul, eBay has already experienced significant business successes through its data analytics. eBay employs 5,000 data analysts to enable data-driven decision making.

Third party

In 2006 the accounting software company Intuit launched a web-based donation tracking service called ItsDeductible. The service uses data from eBay to help users assign a market value to the items they donate.

Visual search

In July 2017 eBay released an image search capability allowing users to find listings on the site that match an item depicted in a photo, using artificial intelligence and machine learning technologies.

GCHQ

UK's GCHQ has a suite of tools for monitoring target use of eBay, named ELATE.

Items

Millions of collectibles, decor, appliances, computers, furnishings, equipment, domain names, vehicles, and other miscellaneous items are listed, bought, or sold daily on eBay. In 2006, eBay launched its Business & Industrial category, breaking into the industrial surplus business. Generally, anything can be auctioned on the site as long as it is not illegal and does not violate the eBay Prohibited and Restricted Items policy. Services and intangibles can be sold, too. Large international companies, such as IBM, sell their newest products and offer services on eBay using competitive auctions and fixed-priced storefronts. Separate eBay sites such as eBay US and eBay UK allow the users to trade using the local currency. Software developers can create applications that integrate with eBay through the eBay API by joining the eBay Developers Program. In June 2005, there were more than 15,000 members in the eBay Developers Program, comprising a broad range of companies creating software applications to support eBay buyers and sellers as well as eBay Affiliates.

Numerous government and police agencies around the world now use eBay as well as traditional auctions to dispose of seized and confiscated goods.

Controversy has arisen over certain items put up for bid. For instance, in late 1999 a man offered one of his kidneys for auction on eBay, attempting to profit from the potentially lucrative (and, in the United States, illegal) market for transplantable human organs.

Beginning in August 2007, eBay required listings in "Video Games" and "Health & Beauty" to accept its payment system PayPal and sellers could only accept PayPal for payments in the category "Video Games: Consoles". Starting January 10, 2008, eBay said sellers can only accept PayPal as payment for the categories "Computing > Software", "Consumer Electronics > MP3 Players", "Wholesale & Job Lots > Mobile & Home Phones", and "Business, Office & Industrial > Industrial Supply / MRO". eBay announced that starting in March 2008, eBay had added to this requirement that all sellers with fewer than 100 feedbacks must offer PayPal and no merchant account may be used as an alternative. This is in addition to the requirement that all sellers from the United Kingdom have to offer PayPal.

Further, and as noted below, it was a requirement to offer PayPal on all listings in Australia and the UK. In response to concerns expressed by the Australian Competition and Consumer Commission, however, eBay has since removed the policy on the eBay.com.au website requiring sellers to offer PayPal as a payment option.

On April 24, 2006, eBay opened its new eBay Express site, which was designed to work like a standard Internet shopping site for consumers with United States addresses. Before it closed in 2008, selected eBay items were mirrored on eBay Express, where buyers used a traditional digital shopping cart to purchase from multiple sellers. The UK version was launched to eBay members in mid-October 2006, but on January 29, 2008, eBay announced its intention to close the site. The German version, eBay Express Germany, was also opened in 2006 and closed in 2008.

At the 2008 eBay Developer's Conference, eBay announced the Selling Manager Applications program (SM Apps). The program allows approved developers to integrate their applications directly into the eBay.com interface. The applications created by developers are available for subscription by eBay members who also subscribe to Selling Manager.

eBay maintains a number of specialty sites including the discussion boards, groups, answer center, chat rooms, and reviews and guides. eBay's mobile offerings include SMS alerts, a WAP site, Java ME clients, and mobile applications for Windows Phone, Android OS, and Apple iPhone.

The initiative Choice in eCommerce was founded on May 8, 2013, by several online retailers in Berlin, Germany. The cause was, in the view of the initiative, sales bans and online restrictions by individual manufacturers. The dealers felt cut off from their main sales channel and thus deprived them the opportunity to use online platforms like Amazon, eBay, or Rakuten in a competitive market for the benefit of their customers.

Unusual items

Many unusual items have been placed for sale on eBay, including at least two previously undiscovered species, including the Coelopleurus exquisitus sea urchin.

Prohibited or restricted items

In its earliest days, eBay was nearly unregulated. However, as the site grew, it became necessary to restrict or prohibit auctions for various items. Note that some of the restrictions relate to eBay.com (the US site), while other restrictions apply to specific European sites (such as Nazi paraphernalia). Regional laws and regulations may apply to the seller or the buyer. Generally, if the sale or ownership of an item is regulated or prohibited by one or more states, eBay will not permit its listing. Among the hundred or so banned or restricted categories:

Bidding

Auction-style listings

Bidding on eBay (old or new)'s auction-style listing is called proxy bidding and is essentially equivalent to a Vickrey auction (sealed-bid), with the following exceptions.

• The winning bidder pays the second-highest bid plus one bid increment amount (that is, some small predefined amount relative to the bid size), instead of simply the highest bid. However, since the bid increment amounts are relatively insignificant compared to the bid size, they are not considered from a strategic standpoint.
• The highest bidder's bid is sealed, as in a Vickrey auction, but the current winning bid (second highest plus one increment) is displayed throughout the auction to allow price discovery.
• Because eBay's auction-style listings are sealed-bid, it is usually to all bidders' advantage that bids are made only at the very end of the auction (except for an initial minimum bid, that cancels out a "Buy It Now" option, or prevents the seller from ending the listing early). Early bids will usually not increase the bidder's chance of winning the auction, and will often raise the item's final price (winning bid) for the eventual winner.
• eBay also allows sellers to offer a "Buy it Now" price that will end the auction immediately. The Buy It Now price is available until someone bids on the item, or until the reserve price is met. When the Buy It Now option disappears, the auction-style listing proceeds normally.

Seller ratings

In 2008, eBay implemented a system of seller ratings with four categories. Buyers are asked to rate the seller in each of these categories with a score of one to five, with five being the highest rating. Unlike the overall feedback rating, these ratings are anonymous; neither sellers nor other users learn how individual buyers rated the seller. The listings of sellers with a rating of 4.3 or below in any of the four rating categories appear lower in search results. Power Sellers are required to have scores in each category above 4.5.

In a reversal of roles, on January 24, 2010, Auctionbytes.com held an open survey in which sellers could rate eBay, as well as competing auction and marketplace sites. In the survey, users were asked to rank 15 sites based on five criteria: profitability, customer service, communication, ease of use, and recommendation.

eBay was ranked 13th, after other large sites such as Amazon and Craigslist, as well as lesser-known selling sites such as Atomic Mall, eCRATER, and Ruby Lane. In individual category rankings, eBay was rated the worst of all the 15 sites on customer service and communication, and average on ease of use. Some respondents stated they would have given eBay a rating of 10, three to five years ago. eBay was rated twelfth out of fifteen in the Recommended Selling Venue category.

Charity auctions

Using MissionFish as an arbiter, eBay allows sellers to donate a portion of their auction proceeds to a charity of the seller's choice. The program is called eBay Giving Works in the US, and eBay for Charity in the UK. eBay provides a partial refund of seller fees for items sold through charity auctions. As of March 4, 2010, $154 million has been raised for US nonprofits by the eBay Community since eBay Giving Works began in 2003.

Some high-profile charity auctions have been advertised on the eBay home page. As of June 2010, the highest successful bid on a single item for charity was for the annual "Power Lunch" with investor Warren Buffett at the famous Smith & Wollensky Steakhouse in New York. The winning bid was $2.63 million with all of the proceeds going to the Glide Foundation. The winning bidder was not made public, but was able to bring up to seven friends to the lunch. In 2012, a higher bid, of $3.46 million, also going to the Glide Foundation, won a lunch with Buffet. In 2016 an anonymous bidder won a $3.45 million lunch with Warren Buffett and the money raised from the auction was given to Glide Foundation.

The previous highest successful bid on a single item for charity was for a letter sent to Mark P. Mays, CEO of Clear Channel (parent company of Premiere Radio Networks the production company that produces The Rush Limbaugh Show and Glenn Beck Program) by Senator Harry Reid and forty other Democratic senators, complaining about comments made by conservative talk show host Rush Limbaugh. The winning bid was $2,100,100, with all of the proceeds going to the Marine Corps-Law Enforcement Foundation, benefiting the education of children of men and women who have died serving in the armed forces. The winning bid was matched by Limbaugh in his largest charity donation to date.

In 2007; eBay Canada partnered with Montreal-based digital branding agency CloudRaker to develop a campaign to raise money for Sainte-Justine children's hospital in Montreal. They aligned themselves with Internet phenomenon Têtes à claques to create an eBay auction based on popular T-A-C character Uncle Tom, an infomercial host who pitches absurd products. eBay and CloudRaker reproduced Uncle Tom's imaginary products, The Body Toner Fly Swatter, The Willi Waller Potato Peeler, and the LCD Shovel and sold them online. In six weeks, they raised $15,000 for Hôpital St-Justine with one fly swatter, one potato peeler, and one shovel, a world record. The Body Toner Fly Swatter sold for $8,600, the Willi Waller Potato Peeler sold for $3,550, and the LCD Shovel sold for $2,146.21.

Shipping

During auction setup, eBay provides shipping-method choices to sellers: ordinary mail, express mail, and/or courier service. The seller may choose to offer only one shipping method to buyers, or the seller may offer buyers a choice of options.

Very-low-value items shipped directly from China are sometimes shipped by surface mail (seamail), which is inexpensive but takes one to two months. If the buyer is in a hurry, he or she might be able to pay an extra fee to upgrade to second-class Surface Air Lifted shipping or to first-class airmail shipping.

Since 2012, eBay has been enlisting sellers into its "Global Shipping Program". If a seller uses the program, non-domestic buyers pay a fee to Pitney Bowes. The seller sends the item to a Pitney Bowes facility in the US (or the UK), which then forwards it to the buyer, taking care of all international shipping requirements. The program is claimed to enhance the product selection available to international buyers.