Getting a personal recommendation from a friend has always been a great way to snag a job. But these days, you might not even get an interview if you don’t have a personal contact at the company!

Experts say the job-search scene has changed because employee networks on LinkedIn and Facebook can help companies find candidates more quickly. They also make it easy for hiring managers to uncover connections between job applicants and current employees.

Most companies still look at every résumé they get, but referrals save a company time and money. The fact is that a candidate with a referral is twice as likely to land an interview as other applicants. And those who get interviews are 10 times more likely to be hired, while résumés from other sources – like corporate Web sites, Internet job boards, and job fairs – tend to sink to the bottom of the pile.

Right now, at big companies like Ernst & Young and Enterprise Rent-A-Car, workers are finding around half of all new hires. And are being encouraged to make recommendations with incentives, like cash bonuses and iPads. But the trend also makes it harder for applicants who don’t have connections. That’s especially true for people who’ve been unemployed a long time because the longer you’re out of work, the fewer connections you have.

So, why are referrals so hot? They tend to fit in faster because they already know someone at the company. They also tend to perform better than other workers, and are 15% less likely to quit.