I have seven frequent flyer memberships, which I signed up for because of different circumstances.
Delta SkyMiles
This is my main program (both overall and for SkyTeam), and I've had it for 11 years now since my mom signed me and my sister up for WorldPerks when we moved to the United States. Whenever we had to fly to the Philippines (or, since 2005, to the U.S. since my sister and I moved back), my mom would only put us on
NW because she preferred transiting in airports like
DTW or
MSP, which are "smaller" according to her than big-city airports like
LAX,
ORD or
JFK.
Since this is my primary FFP and all my long-haul flying is consequently only done on SkyTeam carriers as a result (KL primarily in the last two years), I earned Silver Medallion status in 2010, and if my estimates serve me right, I'll be keeping status until at least 2013 given my current flying patterns. I also have earned 140,000 lifetime miles to date. Coincidentally, until I go to the U.S. for the first time in three years next week for Christmas, I earned status without having flown
DL, neither before nor after the merger with
NW.
Thai Airways Royal Orchid Plus
When we flew to
ATH in 2004 for my aunt's wedding, my grandmother didn't want to waste the miles, so we signed up for Royal Orchid Plus. Status is pretty easy to earn (15,000 miles to earn Silver), but with most fare buckets on European airlines earning little or no miles with
TG when flying intra-Europe, I replaced this with another program in 2010. My membership though still exists (I think, based on the last time I checked), and I'll consider using it if I need to.
Philippine Airlines Mabuhay Miles
Signed up for this in 2009 when I flew
PR to
NRT, and I use it to earn miles when I fly
PR. My dad used to have status for several years (both Elite and Premier Elite) until he stopped most domestic flying with
PR in the early 2000s, having shifted to
5J,
2P or
Z2 instead, and buying
PR tickets only when there's a promo (where mileage is normally only 25% or none at all).
Continental Airlines OnePass
Currently my main Star Alliance program. Signed up for it in 2010 when I flew to Poland for a conference, and I had legs on
LH and
SK which were not creditable to Royal Orchid Plus, although I was thinking of signing up for it as early as the
NW-DL merger, when the threat of miles expiring with
DL was looming. I'll be crediting some
LO flights too next year, and I hope the switch to Mileage Plus will bide well for me, especially since I signed up for OnePass knowing that my miles won't expire.
Cathay Pacific Asia Miles
Signed up for the program when I flew
CX in August, and this is the program of my stepmom, but since Asia Miles is useless for earning miles intra-Europe on most fare buckets, I moved to another program.
Malév Hungarian Airlines Duna Club
Currently my main oneworld program. Signed up for it last month when I flew
MA to
BUD in response to Asia Miles being useless for most discount fare buckets in Europe and for
MA altogether. I read about the status-match offer on FlyerTalk, and I'll be availing of it hopefully by next year. Unlike other FFPs, my approach to this one is segments over miles: earning status with
MA takes 40,000 miles or 15 segments, and 15 segments seems doable if I fly often enough. (Hopefully
MA doesn't tank.)