Avast is a popular anti-virus program that you can download and use entirely for free, with the company hoping that you'll like their product enough to buy a full license. Despite the try-it-forever price of $0, people still pirate the full version, and rather than freaking out about this, the company decided to just watch what happened as one particular license key got stolen like crazy.
This specific software license key for Avast anti-virus was sold to a small company in Tucson, Arizona in June of 2009. By late 2010, the same license was being actively used by 774,651 different people in over 200 countries. Russia was responsible for about 9% of the software pirates, the US was number six on the list, and two computers were identified as being located within the Vatican.
Instead of going and remotely nuking all of the pirated software, the guys at Avast have decided to simply send everyone using it a friendly little pop-up message letting them know that they've got a pirated license and offering them the chance to upgrade for real. This is pretty nice of Avast, considering that three-quarters of a million people are responsible for pirating just this one single key for a product that works perfectly well if you just legally download it for free.
Full disclosure: I use the free, legally downloaded version of Avast myself, and it's great. Take that, Vatican City.