I fly too much.
There are three major airline alliances in the world, Star Alliance (Notable partners: US Airways, United, Lufthansa, and Air Canada), oneworld (American Airlines, British Airways, Cathay Pacific) and SkyTeam (Delta, Northwest, Continental, and KLM). The major benefit of these is earning miles on fewer airlines: if I fly on United, I get miles on US Airways (or vice versa). In effect, you need 3 frequent flier programs to cover the major US carriers. (Jet Blue and Southwest are different - they don't partner, and their miles expire much more quickly)
Well, not only can you earn miles for free tickets, but you can also earn status. Well, I thought that was cool - I flew so much on United and US Airways this year that I got Silver Preferred on US Airways. But the problem is I will probably start flying United a lot more as my work trips to Pittsburgh are going to lessen. And if I had status on United, I could get cool things like Economy Plus seats.
Well, here's the airlines' dirty little secret: you can ask for matching status on other airlines. Today, I requested status on American and United. And you can too. Sometimes you might have to ask for it through a travel agent, or you fax things in. But don't forget this, if you ever fly too much - you can be 'cool' on many airlines even if you don't fly with them much. I know that right now, I select slightly more expensive United or US Airways tickets because I get more miles. Other airlines are smart to compete with that bonus to level the playing field.