This seems to be my biggest problem. How do you group keywords tightly when you have lets say 100,000 Keywords......OR even 5000 keywords. Are people that are having large amounts of success really creating hundreds of adgroups for the same offers? Currently I will take an offer and create around 15 different adgroups with around 300 or so keywords in each. What is the best way to group keywords (in general)? I understand it might be slightly different for particular offers.
For me, it all depends on what you're aiming for. In general, I like to do a splatter campaign (throw everything at the wall and see what sticks) and then from there, generate smaller groups out of the ones that convert. Until you figure that out though, a couple hundred ad groups for a single offer isn't out of the question. That's my $0.02.