Corporate alumni programs, which provide networking, discounts, philanthropy – and maybe a chance to hire back former employees.

It used to be that when you left a job, you were gone. Perhaps you kept in touch with a couple of work friends, pinged your boss for a reference when changing jobs, and maybe even referred someone to a job when you heard about an opening. But that was it.

Corporations have been changing that – realizing the value of former employees that they’ve already put time and resources into, they’re doing it with corporate alumni programs. In fact, 8% of Fortune 1,000 companies have corporate alumni programs, reports Quartz at Work in a story about the trend.

Welcome back to the old job

What does it mean to be an alumnus of your former corporation, and what does do you both get out of it?

For ex-employees, there are reunions, and networking opportunities, and discounts.

For corporations, former employees offer something even more valuable:  they are “viewed as customers, brand ambassadors, sources of referrals, and even future employees,” writes Quartz.

Come back – or stay

Microsoft is an example of a corporate alumni program done right: 15% of Microsoft’s hires are “boomerangs,” meaning employees who left and came back.

Called the Microsoft Alumni Network, it is its own nonprofit group not associated with Microsoft. Ex-employees started the Network in the mid-1990s, and there are 20,000 active members today. Besides networking, they get perks like shopping at the company store, receiving discounts at retail stores.

Deloitte provides networking opportunities, puts out a newsletter, offers training on polishes resumes and digital interviewing.

But it’s not just about white-collar professional workers, either: Taco Bell has an alumni program, too. Former fast-food workers who have gone on to success are held up as models for current fast-food workers in order to promote employee retention in a high-turnover industry – in hope, perhaps, that they’ll say, “Yo Quiero Taco Bell!”