For the first time ever, Rovio is giving away its original Angry Birds for free. The original Angry Birds ever since its existence has always been a paid app, it's never even had a moment to be free to download, till today.
However the reason it's free might not be just down to good will, it might be because Rovio is falling behind hugely in the App Store. People have noticed that Rovio has fallen out of the top 80 highest grossing iPhone apps, for the first time ever since May 2010. This must be worrying Rovio, because their main source of revenue is from their games. Their games now do have in-app purchases though which I'm sure they're hoping will bring in revenue instead of just selling the app.