Hipsters and wannabe urbanites who move from suburban wastelands to NYC believing they will make it big in business, Broadway, or some other NY industry. Eventually, these mid-western suburbanites leave NYC generally after 1-2 years, after they realize they can't take the fast paced culture of NYC, get frustrated, and move to a more laid back city out west (Los Angeles, Seattle, or even back home). Those who expire are generally replaced with another hipster-suburbanite, who will eventually reach his/her expiration date, and the cycle continues.
Hipster E. village kid from Washington: Hey wheres Thom?
Hipster from Idaho: Oh, ya, Thom reached his New York City expiration date, he Got the F*** out before he reached his breaking point.