Yeah, generally you either use someone who has valid code, or you live with the errors. Since they're ads, they shouldn't affect the general page set-up or anything. We recently started using this nasty code from a company called TradeDoubler. The Javascript is nasty, it has VBscript in it, and it makes this HTML that is sooooo nasty and invalid, multiple ads means you have multiple boxes with the same id, blah blah. A pox on them! So I just tried to minimise the damage as best I could by wrapping every ad in its own div with its own unique ID so that I could at least position the divs ok. The code inside, I can't do anything about, and yesh, the pages are now invalid. Were browsers unforgiving XML parsers then we'd be in trouble. But, they aren't, and won't be anytime in the future.