Demand Media, a Santa Monica, Calif.-based digital content and media company, last week paid $17 million in cash and stock for Saatchi Art, which offers works by 45,000 artists online.
Sotheby's said last month it's forming a partnership with eBay to expand its auctions to the online marketplace's 149 million buyers. Amazon Art was started by Amazon.com in 2013 to sell fine art from international galleries.
On Monday, a group of six regional U.S. auction houses will start BidSquare, an Internet platform selling art and collectibles. It will feature a free database of more than 600,000 auction results.
Auction houses, galleries and Web-only companies sold more than $3.3 billion of art online in 2013, or 5 percent of total sales in the global art market, according to a report compiled by Clare McAndrew, founder of Dublin-based consulting firm Arts Economics.
Early upstarts including Artspace, Artsy and Paddle8 have received millions of dollars from investors, including Google Chairman Eric Schmidt. Now bigger players in the art world are muscling in. Christie's, the world's largest auction house by revenue, has allocated $50 million for its digital platform in the past three years.
Companies can make money online by expanding their customer base or by offering more exclusive and expensive artworks, said Clayton Press, who teaches art, commerce and technology at New York University.
Artspace has the base: its mailing list includes 150,000 active art collectors, Catherine Levene, co-founder and chief executive officer of the Internet startup, said.
That number is significant, said New York-based art collector Peter Hort.
"If it's 150,000 people who are collectors of contemporary art, taste makers, gallerists, critics and curators, that's impressive," he said.
Artspace gained access to about half of its list by acquiring the VIP Art Fair in 2013. VIP started selling art online in 2011 with 138 participants from 30 countries, including top international galleries Gagosian, David Zwirner, White Cube and Hauser & Wirth.
VIP's list had contact information for about 75,000 people, including important clients of galleries, according to Jonas Almgren, a VIP co-founder and investor.
"That list included pretty much all the major high-end collectors at the time, people in the U.S., Russia, Europe, South America and Asia," said Almgren. "For Artspace the database was the main appeal."
There's purchasing power behind the lists. NYU's Press estimates that there are 150,000 to 200,000 collectors globally who spend more than $50,000 year on contemporary art. By comparison, Christie's has a list of as many as 145 international collectors capable of spending $50 million or more on art, according to Brett Gorvy, Christie's chairman and international head of postwar and contemporary art.
The auctioneer's catalogs for the evening sales of postwar and contemporary art go out to 7,000 subscribers, of which at least 5,000 have the financial means to bid between $1 million and $5 million, Gorvy said.
At its most expensive auctions, Sotheby's has 1,200 to 1,500 people in a salesroom and about 200 people on the phone, William Ruprecht, Sotheby's chief executive officer, said during an Aug. 8 earnings call with investors. With the eBay pact, Sotheby's will have access to "as much as 100 million plus people," he said.