Microsoft has introduced its second iPhone application in the past month, a free service called Tag Reader that allows users to snap photos of interactive 2D bar codes and immediately be transported to more information. (Maps, videos, music, promotions, etc.) That means mobile phone users don't have to type in long URLs from a mobile browser.

One can imagine a number of real world uses of the technology. For example, a museum could place one of the interactive tags next to a painting. An iPhone user with Tag Reader installed could then take a photo of the bar code and be transported to a video of how the artist created the work.

The introduction of Tag Reader follows the debut of Seadragon Mobile, a photo zoom and browsing technology that was Microsoft's first iPhone application. At the time of the release of that app, TechFlash reported that the iPhone presented some interesting business issues for Microsoft since the popular device competes directly with its Windows Mobile operating system.

More information on Tag Reader on  this informational site, which describes how publishers and other businesses can incorporate the mobile tags into billboards, print ads and other media.

"Make your offline media more effective, more measurable, more immersive, and more fun," the company writes. "Turn your advertisements, media, signage, packaging or storefronts into interactive experiences." The bar codes can be printed and then displayed on a number of surfaces.

Microsoft dubs the technology behind the product High Capacity Color Barcodes or HCCBs. Developed by Microsoft Research, the the bar codes -- which use geometric patterns and various colors -- can store twice as much information as traditional 2D bar codes, the company says.

Hat tip to Neowin.net, which notes how the technology is similar to QR Codes.