I've seen that advice about maintaining several ad groups before, but I'm still a bit skeptical. I've assumed ad groups are just an internal convenience tool fo

I've seen that advice about maintaining several ad groups before, but I'm still a bit skeptical. I've assumed ad groups are just an internal convenience tool for advertisers and that all the ads get dumped into the same auction in the same way in the end. Has it been shown somewhere that Google really uses information about your groupings when it displays the ads?