Similarly, many of us are very aware that it is increasingly expensive to acquire new users. In fact, instead of targeting obvious audiences (e.g. young moms), it is often more effective to try to identify lateral audiences that aren’t targeted as heavily. The percentage of users that click might be lower and the audience might be lower, but the lower cost per user can lead to a healthier return on investment (ROI).
It can definitely be frustrating: not only do you have to think about your ideal audiences, you need to think about how your competitors are eyeing those same audiences or keywords.
One good way to identify alternative audiences is to look at the traffic from your existing users. Google Analytics has added their new Demographics and Interests information and that could be explored for potential audiences.
I sometimes take a “long tail” approach and find smaller audiences/keywords that don’t necessarily have a high traffic numbers but that are relatively inexpensive. You’re not necessarily going to get a big bump in daily numbers, but you’ll have an efficient spend and that additional traffic never hurts.