Outdoor Advertising

I have already seen a lot of outdoor ads, but there are only very few ones that I can remember. This seems to be one of the disadvantages of outdoor advertising when using 'usual' things like for example signs: people look at them when they drive by and sometimes this time period is really too short to remember anything. This is why outdoor advertising has to really be special and outstanding in order to attract people's attention and stick to their minds especially in a country like the US where there is lots of signs advertising certain products everywhere. There are a few outdoor ads, though, that I can still remember, because they attracted my attention and caught my interest. One of them was an underwater ad for Coke in a pool. One could only see it when one would stand on the diving board, but it looked fun and zappy, just like the product the ad was for. I also once saw a really nice outdoor advertising on the front doors of a store. It said "look inside" and then the sliding doors would open to both directions and one could walk into the store to 'find out'. Of course, I will also always remember the huge billboards on Times Square in New York City, but I do think that for effective advertising something like this is even a little too much, because one does not concentrate on single ads anymore and the whole scenery is just one big impression. Therefore I think it would be more effective if there was only one, maybe two huge billboards on Times Square instead of lots of them. Needless to say that this is impossible, since everybody wants to put their advertising on this exact spot, because millions of people are exposed to it every day. I still do think, though, that it is not as effective as it could be.