Online grocers ignite niche battle with national chains.

When HomeGrocer.com began making deliveries to local consumers on May 18, it became the first online service to let Portland shoppers order all their groceries via computer. It won't be the last.

The Seattle start-up is just one of many online grocery companies to spring into existence in recent years. But the competition extends beyond those small technology companies. Safeway. Albertson's and the nation's other major supermarket chains are hardly going to cede the online market to these newcomers, observers say. Not only is it their bread-and-butter, but they've got the food distribution systems, the marketing muscle, extensive customer data and the access to capital to help make it work.

Some major chains, including Portland's Fred Meyer Inc., say they have no projects underway designed to take them into the online marketplace. But retail analysts said each of the brick-and-mortar giants is exploring the …