Bob Fila / Chicago Tribune In November, Gap Inc. jumped into the arena with its online shoe store called Piperlime.com.

CHICAGO Kiran Advani shops for most of her clothing online. In fact, the 29-year-old can't remember the last time she bought a piece of apparel from a store.

But shoes? That's a different story.

Advani never considered buying shoes online until last summer. Frustrated by her inability to find a pair of simple yet stylish pumps for her wedding, she stumbled upon BlueTuxShoes.com, a Chicago-based Web site that specializes in wedding shoes. She found the sought-after pumps and has been shoe shopping online since.

"Now I'm hooked," Advani said. "I was always hesitant about buying shoes online because of the fit and comfort. Sometimes I'm a 7. Sometimes I'm a 7. The last few years I've been doing a lot of apparel shopping online and now shoes have just become a part of it."

When it comes to online retail, footwear has been a step behind the categories driving e-commerce, items such as computers, books, music, toys and clothing. Now shoes are moving into the mainstream.

In November, Gap Inc. jumped into the arena with its online shoe store called Piperlime.com. In January Amazon.com Inc. followed suit by unveiling its shoe site, Endless.com.

"Apparel was the big behemoth," said Catherine Beaudoin, senior vice president and general manager of Piperlime. "It's falling like dominoes. Shoes are probably one of the last bastions, because the feeling has been you have to try on shoes to feel comfortable."

In 2002 online footwear sales, at $954 million, was about one-fifth the size of the $4.4 billion online apparel business, according to Forrester Research Inc. of Cambridge, Mass. Last year, footwear had surged to $2.9 billion, or about one-third the size of the $9.6 billion sold in apparel.

There is more growth ahead. Online shoe sales are projected to increase 22 percent in 2007 to $3.5 billion, compared to an 18 percent projected gain for apparel sales online. By 2011, online shoe sales are forecast to double to $5.8 billion..

In a sign of how popular online shoe shopping has become, two of the largest online shoe stores Zappos.com and Shoebuy.com, both pioneers from the late 1990s are attracting investor interest.