Adobe is stating that mobile Flash will no longer be developed:

Our future work with Flash on mobile devices will be focused on enabling Flash developers to package native apps with Adobe AIR for all the major app stores. We will no longer continue to develop Flash Player in the browser to work with new mobile device configurations (chipset, browser, OS version, etc.) following the upcoming release of Flash Player 11.1 for Android and BlackBerry PlayBook. We will of course continue to provide critical bug fixes and security updates for existing device configurations. We will also allow our source code licensees to continue working on and release their own implementations.

Although this seems like a major shift in strategy, Adobe has been moving in this direction for some time. At the MAX conference last month the company was clear that most web developers can be expected to use HTML 5 rather than Flash most of the time, reserving use of the plug-in for video, games and certain kinds of application. As for mobile, all the talk was about AIR and the captive runtime, an approach similar to the iOS packager which bundles the Flash runtime into your application so that no plug-in or additional download is required.

This approach is now explicit, and I reckon we can further conclude that if the Flash plugin for mobile is being abandoned, then the Flash plugin for the desktop is also less important than before. Mobile browsing is huge, and likely to grow, so developing web pages for Flash is unattractive other than in cases where there is an easy way to direct mobile browsers to a non-Flash alternative. Flash as a browser plugin will now decline forever, which is a good thing for web standards even if it is not necessarily a good thing for web developers, who must face the challenge of cross-browser development.

So what is Flash now? It is still Adobe’s runtime, and the client for its media services, and in that role it remains significant. Thanks to Adobe’s packaging work, you can take your Flash or Flex application and deploy it to most desktop and recent mobile platforms, though not to Windows Phone or older Android devices. Could you not use HTML 5, JavaScript and PhoneGap instead? Maybe in some cases; but Flash is a richer, faster and more consistent platform, as well as benefiting from Adobe’s design and development tools.

See also my piece for the Register: Down but not out: Flash in an HTML5 world.

Update: Added official Adobe link for statement on mobile Flash.