It gets in the way
I have advised people to avoid flash on their websites for a long time now. Initially the reason was one of simplicity. Flash splash pages were all the rage wowing visitors with animated movements and keeping them from getting to what they came for.
It lets hackers in
It wasn’t long before flash became a point of vulnerability. As web use increased the amount of nefarious actors increased and the flash elements provided a weak point in the site allowing the criminal element to gain a foothold toward bringing down your site or using it to promote their own message.
It is blocked in too many places
Many workplaces and schools block flash altogether due to it’s vulnerabilities. If your visitor has an iphone he wont be able to see the flash elements as Apple doesn’t allow flash on ios due to it’s vulnerabilities.
Keep an eye on Jean Barlow’s site I see the world childrens book. I was finally able to convince Jean to switch from flash to html5. I will recreate her page turning book using jquery and css3. I will update this post with the time involved and any limitations of the html5 method.