Calgary-based Critical Mass won the account, whose billings were undisclosed, after a four-month review that included finalists frogdesign, Austin; Interpublic Group of Cos.' Zentropy, Los Angeles; and Omnicom siblings Tribal DDB, Organic and Razorfish.
Dell consumer, small-business and enterprise advertising is handled by Omnicom's DDB Worldwide, Chicago.
Dell has primarily handled work on its premiere Dell.com site in-house.
"We'll work on anything that pertains to the content, look and feel, the user interface and experience of Dell.com," said Jerry Johnston, CEO of Critical Mass.
The agency is already working on content upgrades across all Dell divisions. A site redesign is expected by next year. Mr. Johnston said at least three staffers will be based at Dell headquarters; the Chicago and Calgary offices will oversee the acount.
Critical Mass counts Mercedes-Benz and Procter & Gamble Co. among its clients.