Grow Your Site, Keep Your Users

Computerworld - Online auction site eBay is big. Very big. "We have over 24 million users right now," says Laura Borns, senior usability engineer at San Jose-based eBay Inc., "and over 6 million items for sale." Every day, eBay serves its users 100 million unique page views. "The site is huge and has just grown tremendously," says Borns.

But sites of eBay's size and growth rate always have special usability concerns, says Kipp Lynch, director of user experience at NerveWire Inc., a management consulting and systems integration firm in Newton, Mass. "You've got this huge amount of data, and there are usually two ways to get at it: search and browse," Lynch says. EBay does search "reasonably well," he says. But when it comes to browsing, taxonomy (deciding which items go into which categories) is tricky.

"Taxonomies are really difficult," says Lynch. "Everyone is always struggling with it; no one has gotten it right." Other large sites such as Sunnyvale, Calif.-based Yahoo Inc. face similar problems, he says.

EBay struggles with its fast growth, constantly turning to users to gauge new designs and taxonomies. The company also tries to keep its Web site design as simple as possible so users can find what they're looking for quickly.

Historical Lesson A few years ago, when eBay designers opted to change the background color of every page from yellow to white, they actually changed the shade of the pages in almost imperceptible increments daily for months, until the pages were finally white. "If they'd flipped a switch and gone from yellow to white, everyone would have screamed," said eBay senior usability engineer Laura Borns. "But no one had any complaints about it, because it was so gradual."

"The user interface that worked three or four years ago doesn't necessarily work now. Who knew that when we were designing a site with 60,000 items and a handful of categories, we'd so soon have to make it support over 6 million items and thousands of categories?" says Alex Poon, senior director of advanced technology at eBay.

Poon should know; he redesigned eBay's taxonomy in 1999. Because rapid growth can derail many designs, eBay pays extra attention to how well any new feature will scale. "For example, when we redesigned our navigation bar two years ago, we considered placing our top-level categories into the navigation bar but decided against it, knowing that we would eventually run out of space," says Poon.