Microsoft launched Windows Insider in October 2014 with its first public Windows 10 Technical Preview, and by that December the program counted 1.5 million members. It was a solid start, but the company now says that in just over two years numbers have grown 566 percent to 10 million fans.
These people offer Microsoft praise and criticism about new features and bugs, as Redmond's engineers and developers progress towards a new general release, the latest of which is the Windows 10 Creators Update, due out next month.
"We count over 10 million Windows Insiders today, many of them fans, who test and use the latest build of Windows 10 on a daily basis," wrote Yusuf Mehdi, corporate vice president of Microsoft's Windows and Devices Group.
"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."
Mehdi announced the milestone on Microsoft's new social network, LinkedIn, in a post discussing Microsoft's efforts to build a "fan-centric culture" at the company.
"My learning is that you cannot create fans, you have to earn them," he wrote, pointing out Microsoft's focus on "doing the right thing for your customers" and not hastily churning out products that are a "mile wide but an inch deep in value".
Talking about the power of exceptional products, he said he admires Amazon's Echo, Tesla, and Sonos for their respective innovations in smart homes, cars, and home-sound systems.
However, according to Mehdi, the Windows Insider program exemplifies Microsoft's ability to 'create a connection' with customers, which also guides Microsoft's approach to product development.
While Microsoft annoyed some customers in its mission to convert Windows 7 PCs to Windows 10, the Insider program may show a better side of Microsoft's ability to build a fan base.
What Mehdi describes, with the exception of the use of the word 'customers', actually sounds like the approach used by popular open-source projects, such as Cyanogen, which Microsoft cozied up to briefly in a Cortana partnership before Cyanogen Inc's demise.
"Customers should feel like they have joined a community, a family. Don't be a faceless company. Enable your fans to interact with real people at your company, people who are fans themselves. This requires real commitment, time and effort. A fan is not only going to tell you what they think, but they are going to expect to hear back, to see you take action on their feedback," wrote Mehdi.
"If you create the right connection, it is not a token effort of outreach, rather it becomes the very way you build products and communicate about your progress. If you create a real community, then the best thing happens: fans take it over and they drive the process connecting with each other and assuming your product as their own.
"It can be an incredible experience to see it happen, but you have to commit to the responsibility 24 x 7 x 365. We have had one of these unbelievable experiences with our Windows 10 Insider program."