Sometimes you need animation – movement – on a website, but in the past animators have mainly used Adobe Flash. On Apple devices Flash animations simply appear as an empty black box, which isn’t particularly inviting. Given how many iPhone and iPads are in use now, this isn’t an ideal situation.
There is now other software options available to create animations that will work for more viewers. I often use Tumult’s software, Hype which can be used to create animations for websites and animated elements for use in iBooks.
There are several technical issues that need to be considered when using animations on sites. Firstly the file needs to load quickly so the visitor doesn’t get bored and leave, secondly the file type should be a type that the majority of visitors will be able to see.
Recently software developers have worked hard to come up with solutions that work both on old computers as well as smart phones, tablets and modern computers modern ones. Hype uses HTML5 which is a good solution for the majority of visitors.
Update November 2018: I now recommend Lumen 5 for creating videos.