I'm no expert, but I gather that a big factor is ad networks failing to adopt any kind of standards for HTML ads. Make a SWF that meets certain requirements and

I'm no expert, but I gather that a big factor is ad networks failing to adopt any kind of standards for HTML ads. Make a SWF that meets certain requirements and you can use it with any network, but use HTML and every site has different rules about all the sizes involved, whether you can use libraries, how stuff gets cached or doesn't, etc. It's not my area but, but considering it naively I wonder why all the ad networks don't just pick a version of Swiffy, then keep using SWFs with the rule that the content has to play well with swiffy. (Or maybe they already do such things.)