First impressions are important even in web site design. That being said, having a web page use animation to capture the user's attention right from the beginning can be a great asset. On the other hand, giving visitors a stationary flat web site can be somewhat boring.
Flash animations is just one type of animation that can be used. Java applets and animated GIF files can also be used. However, you will soon see that Flash animations may be the better choice for your web site.
Imagine old school animation where a book of many pages was flipped back and forth and the changes in the position caused an animated effect. This is the same principal with animated GIF files. As such, it requires a number of different pictures with changes in the position of certain objects. The visitor's browser displays these different pictures in a continuous loop in a designated order. Unlike flash animations, animated GIF files can take a long time to download.
Flash animations are a good choice because they do not take too long to download and may browsers are compatible with flash. However, you do have to purchase Macromedia software in order to create flash animations. Yet, flash is easier to understand and get the hand of than java applets. In fact, the flash software comes with lessons on the basics of creating flash animations. If these don't help, there are many web sites that offer tutorials as well.