Harvard’s alumni network is legendary. I have colleagues over 50 who’ve never looked for a job outside their Harvard network.

But how many of us managed to attend or graduate from Harvard? Not that many, I suspect.

On the other hand, many of us have worked for great companies—or at least worked with great people. Those corporate alumni networks are just as valuable as your university alumni network.

So, how do you utilize that network? First, join or offer to start an email list. Both Yahoo! and Google offer free group mailing lists, so starting a list only costs your time, not money. If you’re worried about the time required, enlist a few other people and make sure you all share administrative privileges.

Getting started
Once you’ve joined the list, send a re-introduction email to the list. Keep it short and sweet—so people who don’t know you aren’t turned off. And so people who do remember you think, “Oh, there’s Sue. I’m glad she’s here.”

You could say something like this:

“Hi all. I was in HR at GreatCo. Now, I’m recruiting for NewCo. Yes, we do have openings. Here’s the URL (insert link here). Hope to hear from you whether or not you’re looking for a job.”

Sign it with your name and all contact information, and make sure to include your company’s general URL in your signature.

So once you’ve introduced yourself, what do you do? Monitor the list to see who else is looking or offering jobs, ask for help, and offer help.

You might well be the only recruiter monitoring the list, so make sure you look to see who’s a hiring manager or who’s looking. You can never tell how networking with those folks will pay off.

Asking for help is a way to make personal contact with people on the list. You can ask for help about anything: a good plumber, a restaurant, a referral for a good swim program for your kids. And if you want to keep this about work, ask for help with your recruiting.

Here’s an entry point:

“Hi, I’m looking for a very specific kind of project manager for our chemical engineering projects. See the URL (insert the URL here) for the job description. If you or anyone you know fits the job description—or even comes close—please let me know.”

Always end the email with your full name and all contact information.

When people ask a question—and you know the answer—offer help. The more valuable your help, the more people will remember you.

A few caveats
Keep your emails short and sweet. If you’ve already sent an email to your list with one job description, wait a few months to post it again, and tell the list you’re still looking.

Never include attachments with your email. No one wants those attachments, and many people won’t open one. Include a web page URL for viewing job descriptions.

Always include all of your contact information in the body of each email.

Your corporate alumni network may not pay off immediately. But your contributions might make a few more people think of you first—which is exactly what a recruiter wants.