Search engines do not recognize Flash. So, all the flash that you deploy on your website will go completely unnoticed by the search engine robots. All the flash animations, headers made of flash and other elements are of no use from the search engine perspective.
rightio... contradiction! Does anyone know for sure that google now recognises text in flash? image names?..etc I've read that it does, but havn't actually done a test, so can't say for sure if its true yet. When you look at a cached version of a page in google.co.uk with flash - where the flash is meant to appear, there is a gaping hole ??
google say they can read flash now but they say a lot of things. i wouldn't trust it just yet as this new flash reading technology will be subject to teething problems and i would want conclusive proof the engines can index all flash content as well as maintaining navigational context. use flash to augment your text content, not replace it. don't include important textual content or headings in flash and certainly don't use it as your only navigation!
Here is the answer to all your questions: http://googlewebmastercentral.blogspot.com/2008/06/improved-flash-indexing.html