Manage Huge Campaigns? Ad Groups May Not Be Best Bet
One keyword can have multiple attributes, from customer targets, to SKUs, to holiday usage--and forcing it into an ad group based on one particular category can limit its flexibility. This is why the search team at The Rimm-Kaufman Group places keywords into ad groups only if they share all of the same attributes, not just one or two, as the PPC management platforms would suggest.
Michie says that the client drawbacks to this method are minor. Yes, clients may get reports directly from the engines saying that they're "not using ad groups correctly," and at times, it may be difficult to for them to find specific keywords or phrases within the accounts. But the benefits of making swift copy changes across multiple campaigns (without having to break up and recombine ad groups) as well as not constraining bidding according to predetermined, sometimes arbitrary, groupings outweigh the cons tenfold. Besides, with full service campaign management, clients are welcome to dig into any of the accounts they'd like--but they shouldn't need to.