The availability of the Windows 8 Release Preview marks the inclusion of Flash into the operating system, which Microsoft has selectively included to ensure good performance remains. The reasons for that integration has been leaked.

Danny Winokur of Adobe sent an internal memo to employees to explain Adobe's Flash support in Windows 8, which Microsoft has previously said is integral to the Web. In the memo, Winokur said Adobe didn't license the code to Microsoft; instead, Microsoft received "strong customer feedback" on Flash support in Windows 8 and invited Adobe to support the OS.

"We have been working closely with Microsoft to ensure a great Flash experience in Windows 8 and recently finalized an agreement that is the basis for today's release. Our work together has to a large degree focused on integrating Flash Player into Metro style IE10 with special privileges that enable it to run while other plugins still cannot (consistent with Microsoft's earlier announcements about plugin-free browsing). We did this work with their support and cooperation on integrating with IE and Windows. We will deliver future updates to the Flash Player (both security and feature upgrades) through Windows Update in much the same way that Microsoft updates itself," the memo said.

Sharing updates via Windows Update for non-Microsoft products is uncommon. As said, Windows 8 and Flash are unique: the Metro version of IE 10 only supports some Web sites - such as YouTube, and not Rdio - and Microsoft keeps a complete list of all the supported sites. Whether Microsoft will support the most-requested Web sites, or fully roll the software out, is unknown.

Performance is a key part of Microsoft's strategy with Windows 8, especially in Metro. The desktop version of Internet Explorer 10 does fully support Flash.

As The Verge noted, Flash support is a "key win" for Adobe as the company aims to "keep Flash support alive" as HTML5 continues to grow in popularity. Other companies such as Apple refuse to integrate Flash, instead focusing on Web sites built for mobile and HTML5.