That line’s been stuck in my head ever since an editor said it last summer – and it’s 100 percent wrong.

The editor and I were talking about a story I’d done, a case study involving some relatively new and complicated technology. I’d finished writing and, at her request, sent the draft to one of my sources – I know, bad editorial practice but totally not my call – to check that the convoluted tech stuff was factually accurate.

Only when I emailed the story to the source, I’d forgotten to remove some notes at the top that I’d written to the editor, notes that included some less than flattering comments about the source – nothing defamatory, nothing horrible, but embarrassing nonetheless.

That’s what prompted the editor’s comment to relax and forget about it because I’d never be talking to that person again.

It’s advice I promptly ignored.

Maybe that’s the way she does business. But it’s not how I operate.

To make a proper go of it as a freelancer, you’ve got to be a beat reporter, keeping up on the latest news and events in fields you cover. That means keeping in touch with a ever widening circle of contacts, because you never know when you’ll need to talk to someone or ask for a referral to someone they might know.

Over the years, I’ve prided myself in my source list. A friend and former co-worker still talks about the extensive list of contacts I left when she took over my newspaper beat while I went on maternity leave.

These days I use LinkedIn, Twitter and Google Desktop to keep tabs on sources and manage contact information online and within my computer files.

Sources are my pot of gold, my secret weapon. They’re the reason I can take 500-word assignments that only pays 50 cents a word, because I can tap into my source list to turn a story around in less than a day, making it financially feasible when calculating the work on an hourly basis.

I may treasure my sources, but I’m no pushover.  The only times I’d let a source see quotes before they’re published, go off the record or talk anonymously is if the editor asked or the circumstances warranted it. And asking tough questions is par for the course.

After I realized what I’d done and called the editor, I picked up the phone again and called my source. Even from across the the country, I’m sure they could tell my face was red. Luckily for me, they were pretty good about the whole thing and there were no lasting repercussions.

Moral of the story: Never, ever, include notes on a story that you wouldn’t want the world to see. And whatever you do, be good to your sources.

If you don’t, it might be time to get acquainted. HARO stands for “If I Can Help A Reporter Out.” It was started by a PR guy and networking maven named Peter Shankman as a place reporters can turn to when they’re stuck for sources. Shankman started it as an alternative to ProfNet, which some writers have complained has grown so big the sources it nets aren’t relevant.

For reporters, HARO is easy. You don’t even need to register. Just go to the “Reporter” side of the service, fill out the request form and click “Submit it.” Your query will be included in an emailing of multiple requests for sources that Shankman sends out several times a day to a list of more than 23,000 PR representatives, company executives and other sources.

I’d heard a lot about HARO in recent months but didn’t give it a try until last week when I was hurting for sources for an IT industry story for IncTechnology.com that I was writing at the last minute. So I took the plunge and submitted a HARO request. Within 24 hours, I got about 40+ responses from PR reps, IT consultants and company presidents, etc. By the end of day two, I’d received close to 60.

HARO isn’t just for tech stories. I have freelance friends who write about all kinds of things, from green living to parenting to finance, and they all use it and rave about it. And they’ve been able to track down the hardest sources of all to get – real people.

HARO has grown so popular so quickly, it’s now got some of the same problems that plagued other source-finding services, namely too many off-topic responses, which you can read more about in this post about it on The Renegade Writer blog. Get around that by making sure your queries are as specific as possible. And state up front that people won’t hear from you unless you’re interested in using them.

If you decide to give it a try, I’ve got one more piece of advice: since HARO can result in inquiries from many more sources than you could possibly use, when you fill out the query registration form, give a very short time frame for people to get back to you, such as in 24 yours or less. Otherwise you could get bombarded.

And if you’re a PR person, read these great do’s and don’ts from Susan Johnston’s The Urban Muse blog about using HARO to pitch story ideas to writers.