For many years Flash was the standard for rich animations and, later, robust applications on the web. Html, css, and javascript lagged far behind in their capabilities. As those languages grew (along with web standards), so did the capabilities of Flash with the introduction of CS3, enabling business applications for the web scripted in ActionScript3. At this point, Flash was nearly as robust as its older sibling Director, scripted in Lingo. (ActionScript, Lingo, and JavaScript are all derived from the same parent language.) When Adobe bought Macromedia, focus went to web-friendly Flash, leaving Director to languish in limbo for a couple more years. Flash continued to grow.
Enter the mobile device explosion. As mobile devices became more widespread, support for these became as important as that for desktop/laptop devices. Blackberry became one of the early front-runners but Apple, with its enormous marketing machinery, took the lead with a very large share of the market. Most devices supported Flash Player, but Apple refused to allow it on their iOS devices – iPhone, iPad – citing high resource consumption and poor SEO recognition, both highly debated. Apple seems to have won. Adobe withdrew Flash Player support for mobile devices and, while Flash content and scripting can be wrapped in an AIR mobile app for delivery on iOS, the prevailing trend is the use of the newer capabilities of html5, css3, and JavaScript, though these are not yet as capable as Flash.
An additional concern with Flash is security. Adobe has always maintained Flash to be solid software, and secure as well. However, there have been some security issues recently which Adobe is addressing. Real or fabricated, this is another nail in the Flash coffin.
As a Lingo programmer, I dabbled in Flash 3, 4, and 5, then became more committed to Flash 8 and again to Flash CS4 (10), making changes to several existing Flash-based websites, and designing and programming a Flash-based site for New York photographer John Manzi – all prior to the Apple situation and Adobe dropping support for mobile devices. While the demand for Flash/ActionScript programming is not what it once was, I will always have an affinity for Flash (and for Director, for that matter). I welcome any opportunity to work with Flash.