One of LivingSocial's goals this spring was to hire 100 people in 100 days. (It actually accomplished the feat in just 85 days.) Few companies will need to staff up quite that quickly, but any start-up can employ LivingSocial's hiring strategies.

1. Tap social networks
Though the company casts a wide net by using recruiters and online job boards, LivingSocial finds that its best candidates, especially in terms of cultural fit, almost always come from employees' social networks.

2. Let employees weigh in
Recruiters can help screen resumés, but LivingSocial claims its employees are best at judging cultural fit. After telling employees which types of interview questions are illegal and off-limits -- such as inquiries about a candidate's age and marital status -- LivingSocial lets them come up with their own questions.

3. Set expectations
People who have never worked for a start-up don't know how chaotic it can be, says Alan Clifford, LivingSocial's HR manager. "I could promise people that we will give them great support, and that everything about their jobs will be nice and tidy," he says, "but things are hectic. We need people hungry enough to find the answers to their questions. If someone needs a lot of structure, it's not going to work out."

4. Look for entrepreneurial types
LivingSocial looks for go-getters who want to be part of something big, even if it means, say, changing positions three times in a year to meet the company's changing needs. CEO Tim O'Shaughnessy says his dream is for every employee eventually to start a business using skills learned at LivingSocial. "We want people who are driven to create new companies and opportunities," he says.