When you think about geotagging, what do you think of? GPS coordinates appended to a Tweet? Picking the location you took a photo on Flickr?

How about notes from your friends? As customary, the US Patent Office recently published a patent filed by Yahoo in July 2008, and in that patent, geotagging takes on a whole new meaning. Instead of assigning pictures a location, you can actually leave notes at a location, accessible via mobile, and networked with your friends. Want to let your friends know what your favorite restaurant is? Add a tag. When they’re in the area, their phone will let them know about your tag. And that’s just the beginning.

As Read Write Web points out, this dovetails nicely with another patent filed the month before—one that provides video, audio and other info pertinent to the user’s location. This latest patent builds on both these ideas:

The technology described in this latest patent isn’t just location-based social networking, or Augmented Reality “air tagging” – it includes social graph analysis, permissioning, expiration dates, contextual advertising and more. It’s not just text notes, it includes methods of augmented reality with photos, videos and more. While the most popular mobile augmented reality apps on the market today focus on text on top of locations – there’s no reason why reality can’t be augmented in other ways as well.

Notes can also be tied to non-stationary objects, including people (well, more likely their phones) and vehicles.

The patent is not yet granted—once a patent is published, the USTPO reviews it in due time.

Google has made a few location inroads—Latitude to publish users’ locations, a year ago, and “Near Me Now” to offer nearby business suggestions, last month. However, if Yahoo is currently developing the technology to make their patents a reality, Google has a long way to go to catch up.

Yahoo isn’t the first to develop solutions for augmented reality—but they might be the best known. With the huge userbase they already have, they probably stand a better chance than most of the competitors in the field.

What do you think? Will Yahoo pursue this technology—and if so, will they lead the way for mass adoption?