It’s nearly impossible to walk onto a subway, bus or even airplane these days without seeing a fellow traveller with eyes glued to a smartphone, playing Angry Birds in a trance-like state.

To say that Angry Birds is a popular game would be an understatement. By the end of last year, Rovio (the company behind the app) had sold more than 12 million copies of the game via Apple’s App Store.

But that’s nothing: Rovio’s Peter Vesterbacka told TechCrunch in a recent interview that when adding up all the platforms, the game has been downloaded 250 million times.

It’s no secret the addictive game has gotten people talking. A basic YouTube search reveals dozens of Angry Birds spoofs, including a fake movie trailer that has garnered six million views in less than three months.

Rovio is keeping the conversation going with the announcement that Angry Birds will be using location-based technology to integrate the game with the real world. Magic Places, the new feature, will allow users with GPS-enabled smartphones to tap into new content when they go to certain locations. The new feature also allows users to interact with each other while playing Angry Birds.

“We’re using this as a way to encourage people to go and find new places and new content,” Rovio’s Ramine Darabiha told Businessweek. “It will be a distribution point for us.”

This isn’t the first time Rovio has expanded the Angry Birds brand. Mashable reported last month that the company plans on bringing Angry Birds to Facebook – and that’s not all. Back in January, Rovio CEO Mikael Hed confirmed to Britain’s C21Media that the company had plans to work on a series for TV or the web.

The game is no longer only available for smartphones owners, either. PlayStation 3 and PSP users can play the popular game on their consoles. And old fashioned users can also enjoy the game on their computers.

Finally, taking a page from the marketing whizzes at Pixar, Rovio has cashed in with Angry Birds board games, stuffed animals and backpack clips. There’s even a cookbook in the works.

Is Angry Birds an enduring brand or a passing fad? We’ll see. But what’s clear is that it’s yet another example of a web phenomenon landing in the real world.