An old topic, but thought this was funny and to-the-point. Jared Spool of User Interface Engineering, in an article at Marketing Sherpa:
When we have clients who are thinking about Flash splash pages, we tell them to go to their local supermarket and bring a mime with them. Have the mime stand in front of the supermarket, and, as each customer tries to enter, do a little show that lasts two minutes, welcoming them to the supermarket and trying to explain the bread is on aisle six and milk is on sale today.
Here’s a bunch more reasons why Flash intros don’t work. Start with the fact that 80% of users say they hate them, and 25% say they just click away from the page as soon as they see one.