Flash is a file format used to program and display multimedia and interactive content. There are many possible applications for flash (e.g. interactive menus or implementing games and videos on a page). Flash doesn’t only display multimedia content but can also process user interactions through mouse, keyboard and camera.

Flash uses SWF (Shockwave Flash) files that need the free Adobe Flash plug-in to be displayed.

Flash is probably best known because of its use for displaying videos on YouTube. But now there’s another free alternative to display videos: HTML5.

Google can index Flash content but this isn’t the case with all search engines. Google itself recommends not to overuse Flash and use it primarily for decorative purposes.1) You should keep in mind that Flash requires a plug-in to be displayed. This means that users with old browsers or Apple devices can’t see that content.