Microsoft claims it has had unprecedented success in its worldwide efforts to prevent people from pirating or counterfeiting its software.

The company outlined more than 400 law-enforcement efforts in 49 countries on six continents around the world to prevent the piracy or counterfeiting of its software products.

Calling the efforts a "diversity of enforcement", David Finn, Microsoft's general counsel for worldwide antipiracy and anticounterfeiting, said the company "has never been so involved with so many countries doing so many things" to combat software piracy and counterfeiting.

Law-enforcement efforts to crack down against sustained criminal activity to pirate and counterfeit its software and then resell it for profit has been a pet project of Microsoft's for some time. Indeed, Finn said some of the cases are the product of at least five if not more years of effort.

"This kind of co-ordinated effort doesn't happen in minutes," he said. "It really is a lot of work."

Countries as diverse as Argentina, Australia, Kuwait, Nigeria and Pakistan are all regions where Microsoft has been working with law-enforcement agencies to prosecute people for software piracy and counterfeiting. A list of all of the cases the company has been posted on Microsoft's website.

Among the cases Microsoft is publicising include the successful prosecution and sentencing of two people in China who sold customers unlicensed software by forging Microsoft Open Licenses, Finn said. Each of the defendants received a sentence of six months in prison by the Nanning Quingxiu Peoples Court, according to Microsoft.

Another case in Japan is the most significant criminal prosecution Microsoft has seen in that country around this kind of fraud, Finn said. Microsoft Japan this month filed criminal action against an alleged software pirate accused of selling counterfeit versions of Windows XP online that possibly affected 50,000 sales, he said.

Next page: WGA successes - and criticisms

One of the results of Microsoft's years of effort to crack down on software piracy and counterfeiting is an automated software validation system first revealed in 2005 called Windows Genuine Advantage (WGA).

WGA started as an update for Windows XP but then was built into Windows Vista. Concerns were raised in its early days over bugs that would identify people's genuine copies of Windows as counterfeit or pirated, but Microsoft seems to have smoothed out the process since then.

Though it's just one of many tactics Microsoft is using to crack down on piracy and counterfeiting, the software-validation system has been instrumental in finding and prosecuting people around the world for criminal activity around its software, Finn said. Another strategy the company and local authorities have used include sending investigators to make test purchases of software

Open-source proponents who advocate that software should be free from proprietary software licensing restrictions have criticised Microsoft for waging such a relentless legal fight against piracy and counterfeiting. However, Finn said the cases Microsoft is prosecuting around the world are typically not against individuals who may make a copy of Windows or Office and pass it on to their friends.

"We're talking about organised criminal syndicates who earn millions and millions of dollars by defrauding people all over the world," he said. Finn added that often the software they sell to unsuspecting buyers also contains malicious code.