It is easier to remember information seen on an animated site than from a plain text site. My interest in viewing an animation is affected by the length of the animation. I like to be able to interrupt an animation at any point and have full navigational control. If a website has an impressive animated introduction, its online strategy is on track. The more similar the web and television environments become, the better.
Animation is only appropraite on specific web sites.
I would rather see a ten second marketing animation than read a marketing brochure. An animated marketing message should be crisp and quick. Brand building and persuasion are key purposes of animation on the web. If web sites take more than 10 seconds to download I avoid them. If I am well informed as to how long an animation will take to download I will be patient and wait.