This ad ran for about two months. From late November until the end of January. It received click-thrus almost as high as 1% for parts of the campaign. What I really love about this ad is that it was simplistic. It's a pretty good example of creative that isn't being pushed in your face but still extremely effective.
I designed this ad with a few things in mind. For one, I always try to keep as much information above the fold that I can. Knowing the cut off point of many browsers with our site I have a pretty good idea what a user will see on the initial load of a page, and what they won't. I've placed all significant copy above that point and made sure the main message was clear and legible. Since I wanted to use the image prominently in the ad I decided early in the design process that I wouldn't have much room for animation.
Instead of overly compressing the image I left the compression rate pretty high and imported the JPG into Flash MX. Since I wanted to lead the users eyes through the copy and to also enjoy the ad. I used a simple ActionScript to animate the snow effect. I thought it was seasonal and something I haven't seen before in our ads. The ActionScript it pretty small and I am only using one MovieClip that I resize and modify it's properties to speed or slow down it's falling motion.
Overall I think it shows that an ad can be effective without tons of animation, flying across the screen, or with large file sizes.