Banner Ads for Situation
Banners pose an interesting set of challenges. You have a tiny area of space, and the information to convey should fit well in all proportions, whether that be square, or super-duper skinny. Banners at their best are in takeovers, like for example on the homepage of The New York Times, when various sizes are scattered throughout the homepage along with an on-brand background. In those cases, the content from some banners can complement others, rather than one message repeated.