SAN FRANCISCO (Business 2.0 Magazine) - When advanced networks are available everywhere, location data will become the key to determining what kind of information is most relevant at any given time. The obvious location-based services - the ones available today - are basic mapping, direction finding, and Yellow Pages-style listings.

Even better are so-called mashup services that let users create, tag, and annotate their own maps. These have found a niche on the Web, but they'll be even more useful when adapted for wireless use. Some tips will be passive, like a flagged comment that "this restaurant serves good barbecue."

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Others will be more active, making it possible to leave a location-based "note" outside the corner store so your spouse will receive a reminder to pick up some milk when he or she walks by on the way home.

Services that push location-based information to users will have tremendous potential. That could entail letting you know when family or friends are nearby, or it could mean signaling when you're close to an event or attraction that matches your interests. (Naturally, this has marketers salivating at the potential to hit users with timely, location-based ad messages as well.)

Meanwhile, the venerable bar code is likely to play a prominent role in facilitating communication between the mobile and physical worlds. Camera phones will do double duty as input devices for bar-code-recognition software that links information tied to specific places, displays, or attractions, while mobile screens will be able to display bar codes that authorize entry to theaters, concerts, transit systems, or even airline flights.

In many different ways, your mobile device will be your ticket to ride.

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Read more about your wireless future:

• Entertainment: Mobilizing the buddy list
• Tomorrow's wireless devices
• Productivity: The everywhere office
• Voice communication gets more flexible