Regarding your question about adverts being archived, I'm going to give you a boring account exec answer. When it comes to competitive reviews for clients (which is the main reason why you'd want to search adverts), what you need to look at is when and where ads for a specific brand were produced. The actual theme of the advert is largely of little consequence in the client's eyes. Perhaps the only time when it is useful is when creatives want to check whether their ad - or the theme - has been done before. But knowing creatives, they probably wouldn't bother doing that. ;-) Hope that's useful.