In the years since its inception, the Windows Insider Program has steadily come to encompass millions of dedicated Insiders, and now it's crossed a pretty significant milestone: 10 million members. The latest count was revealed in a recent LinkedIn post (via OnMSFT) by Microsoft executive Yusuf Mehdi, who briefly touched on the subject in larger post about about the "fan-centric culture at Microsoft."

Windows Insider Program now sports 10 million members

From Mehdi:

We have had one of these unbelievable experiences with our Windows 10 Insider program. We count over 10M Windows Insiders today, many of them fans, who test and use the latest build of Windows 10 on a daily basis. Their feedback comes fast and furious, they have a relentless bar of what they expect, but it so inspires our team and drives our very focus on a daily basis.

That's some serious growth for a program that only got its start in 2014 with the intention of accommodating only 250,000 testers. Famously, Microsoft opted to open the program up to anyone who wanted to participate just before launching.

The last official numbers we received from Microsoft came in September of 2015, when it sported more than 7 million members. That was an increase over just two months earlier, when the program counted 5 million among its ranks. Obviously growth has slowed a bit since then, but 10 million is certainly nothing to scoff at. And that success has even inspired Insider programs for other Microsoft properties, including Office, Skype, and Xbox.