Alternate Flash Content
Flash content on your page (Flash, an Adobe Product, is used to produced images, graphics, or, in some cases, entire pages) isn't read by Search Engines. Alternate methods can provide text describing flash images to Search Engines. Without employing these methods, extensive use of flash harms search engine results.
"Format Wars" and Flash
As of this writing (2012), many Apple devices do not support Flash. Flash is entangled in a larger set of format wars involving video formats, HTML5, CSS3, and all of the large players (Google, Apple, Adobe, etc.) in the Internet space. It's possible many devices will support Flash, and others won't, for some time. Providing alternate content for Flash isn't just good SEO; it's good web development.
Avoid This: