WASHINGTON — When Jim Neill got laid off, he sent around a farewell e-mail with a subject line designed to get people's attention: "Free food in the employee lounge."

Then Neill, who had been with the National Association of Manufacturers for years, left 'em laughing.

"These are tough times and with a young family I'm hunting for employment," he wrote, "but you'll be pleased to know I've also begun work on my long-delayed book and instructional DVD 'Rhymes with Truck: How to Use Profanity in Every Sentence.' "

There's an art to the goodbye e-mails flooding inboxes as a result of massive layoffs. A few, like Neill's, are laugh-out-loud funny. Some are bitter flameouts. Some read like brief memos or mysteries with no explanation of the move; others are like lengthy Oscar speeches thanking co-workers.

Whatever the tone, they are everywhere; more than 45 million Americans were either laid off last year or left their jobs for greener pastures.

In the days before company e-mail distribution lists, the task of letting friends and colleagues know about your departure was primarily done by phone or through an interoffice memo written by Human Resources.

With the wider reach of e-mail comes some danger: An e-mail will last longer and may pop up into the inbox of unintended recipient.

Lawyer Shinyung Oh's angry goodbye quickly made rounds of legal blogs. Oh was let go from the Paul Hastings law firm's San Francisco branch six days after having a miscarriage. She wrote a blistering e-mail accusing the firm of heartlessness, and sent it to her colleagues.

"If this response seems particularly emotional, perhaps an associate's emotional vulnerability after a recent miscarriage is a factor you should consider the next time you fire or lay someone off," she wrote.

Oh has since started her own blog but would not comment on the incident.

Experts warn against displays of anger over concerns that it could hurt a future job search. Many caution against even a hint of negativity.

"Don't show any bitterness. Don't complain. Just be positive," says Donna Flagg, a workplace expert and the president of The Krysalis Group, a business and management consulting firm in New York.

At its simplest, the e-mail only needs to let friends and colleagues know you're leaving and how to reach you. A goodbye handled properly can even help with the job search.

Neill, who joked about free food in the office lounge, sent a separate, more formal e-mail to outside business contacts, but wanted to lighten the mood inside the office.

"There was a lot of tension in the air," says Neill, who has landed a job as vice president of product safety for the Retail Industry Leaders Association. "I wanted people to feel comfortable saying goodbye. I didn't want anyone walking on eggshells around me. Humor seemed the best way to do that."

Staying professional doesn't mean checking your personality at the inbox. Before Pete Seat, a deputy press secretary under President George W. Bush, left the White House, he sent a goodbye e-mail to friends, White House colleagues and journalists.

"With most of us embarking on a new personal or professional adventure over the next few weeks and months, remember the words of Macaulay Culkin in Home Alone when he said, 'This is it, don't get scared now.' That always helps me," he wrote.

Seat also included a quote from former press secretary Tony Snow, reminding those who have worked in the White House how special it is. "Leave no room for regrets, for someday, in the not-so-distant future, you will be back where you started: On the sidewalk with the folks, gawking at that grand, glorious, mysterious place — where Lincoln walks at night, and our highest hopes and dreams reside."

With that, Seat had the e-mail hat trick: His message was lofty, humorous and satisfied his basic need to get his new contact information out.

"I wanted to have a little bit of fun with it," he said. "It's a silly line from a silly movie, but it does have a practical point to it. Even in uncertainty, we need to move forward."