Zones is an online retailer of computer equipment, both Mac and PC, as well as office equipment and various computer accessories. They have a fairly extensive catalog, with decent prices and sometimes some good specials.
In 1986 they started as a Mac-only store, since then expanding into PC supplies, networking, accessories, office supplies and even IT services, such as account management, e-business services, web shopping and others.
Other online vendors similar to Zones.com include MacMall and PCMall, MacWarehouse and PCWarehouse, and countless other websites that sell computers and more.
Some information taken from Zones' website