Flash is an incredible tool for creating beautiful, vivid websites that often feature animation, video and sound. For some types of businesses and organizations, Flash can be the right choice.
On an iPhone, your website would be invisible. Really! The iPhone operating system does NOT currently support Flash!
With a slow computer, cell phone, or dial up internet service, your page might take FOREVER to load...or take so long that people just leave your site before it downloads!
Flash-based pages are not indexed the same way by search engines. The robots are not able to scan the code to "see" your keywords and learn what your page is about!
If your website uses Flash, provide text based content also...so search engines can find your site and people can see at least some of it.
Flash can we wonderful in moderation, but not as your entire website.
Flash might add some "buggy" side effects to your web page!
in a variety of circumstances & for most people who visit!