On January 21, in a two-hour-plus event at its Redmond headquarters, Microsoft unveiled features that will be appearing in Windows 10 "over the next three, four, five months." Two days later, the company released a new Windows 10 Technical Preview version, build 9926, for anyone who signed up with the Windows Insider program.

If you're eager to get started with the new build, ready my hands-on installation guide first. In this post I cover what'sin Windows 10 and what you can expect through the remainder of 2015.

Two things are worth noting here, especially for people who haven't noticed the big changes in Microsoft's development process lately.
First, preview users will see new features and design changes delivered at a much faster pace than in previous development cycles. After the preview release on October 1 Microsoft released updates approximately every three weeks. In a post announcing the release of build 9926, Microsoft's Gabe Aul says:
The gap between 9879 and 9926 is the longest you should expect to see with the program, because of the holidays and the need to add and stabilize feature payloads. We'll get new builds out faster moving forward...
Second, some features seem incomplete because, frankly, they are. From that same post:
You'll see some big changes to the Start menu in this build, including the ability to expand to a full-screen experience. ... A big change that you won't see is that we actually rebuilt Start in XAML, which is one type of code developers can use to build apps for Windows 10. The work on Start isn't done yet, and we'll have more changes that will show up in future builds including more personalization (and transparency!), drag and drop, Jump Lists, and the ability to resize the Start menu.