From Mac Guides
In 2001, Apple began its foray into the retail, or "brick and mortar," space, reportedly to combat poor representation of Apple hardware and software at many of its retail partners' stores. By the end of November 2005, Apple is on track to open 99 stores internationally, with the bulk of those being in the United States. The online Apple Store is also referred to as "The Apple Store."
Apple has credited its retail effort with helping to increase profits and market share over the last several quarters in addition to simply raising the visibility of the brand. Located primarily in higher-scale fashion malls in the U.S., the Apple Stores have been crucial, at least anecdotally, in Apple's attempt to convince Windows users to switch.
The market dominance of the iPod seems to have been facilitated, at least in part, by the existence of the Apple Stores. Some feel the stores have in fact been transformed to become iPod stores, practically devoted to selling the iPod and related accessories in massive quantities. Others seem to view this as a natural and healthy growth of Apple, and that the success of the Macintosh platform and Apple as a whole — which probably includes convincing at least some Windows users to switch — is tied closely to the Apple Store and the iPod.
Regardless, the reality is that the Apple Stores seem to be a good place for those relatively new to Apple products to purchase and get some support for Macs, iPods, iPads, iPhones and limited, related software and peripherals.
At WWDC 2006, Steve Jobs announced that there were 157 stores, with 17 million visitors during the last quarter. This compared to 135 stores at Macworld San Francisco 2006, with 26 million visitors during the preceding holiday quarter. At Macworld San Francisco 2009, Phil Schiller announced that the stores receive 3.4 million visitors per week.
Genius Bar is a station located inside every Apple Retail Store that offers help and support for Apple products. Apple calls the Genius bar the "heart of every Apple store". Mac "Geniuses" are specially trained and certified employees who staff the Genius Bar and help customers with Apple products in general, as well as certain non-Apple accessories, such as PDAs, printers, and speakers.
Mac Geniuses are primarily the local representatives of Applecare (Apple's name for its support service covering warranties, etc.). They offer personal support when customers have problems or questions with their Apple products. Not all services at the Genius Bar are free; out-of-warranty products are serviced at an additional charge.