Lucky for me (and for everyone, in fact), Jakob Nielsen talks about this very subject in Top Ten Web Design Mistakes of 2005:

Despite such good intentions, most of the Flash that Web users encounter each day is bad Flash with no purpose beyond annoying people. The one bright point is that splash screens and Flash intros are almost extinct. They are so bad that even the most clueless Web designers won't recommend them, even though a few (even more clueless) clients continue to request them.

Flash is a programming environment and should be used to offer users additional power and features that are unavailable from a static page. Flash should not be used to jazz up a page. If your content is boring, rewrite text to make it more compelling and hire a professional photographer to shoot better photos. Don't make your pages move. It doesn't increase users' attention, it drives them away; most people equate animated content with useless content.

I have my own mini-rant on the Flash on my FAQ page, and yet I am asked on an almost weekly basis by otherwise smart people about creating a Flash-based interface or splash for them. It takes every ounce of strength in my body not to jump through the phone lines and grab their shoulders while screaming "WHAT IS WRONG WITH YOU?"

Sigh.

I hope he is right when he says that Flash intros are becoming extinct, because I still see them. All the time.

Thanks to Andy for this.

Flash, Jakob Nielsen, Flash is bad