Heard the one about a bank employee, a fertilizer salesman, a real estate agent and an engineer who walk into a bar?

It wasn’t a joke Wednesday night as nearly 30 people from businesses all over Billings got together for the second in monthly series of “tweetups” to teach them how to use social-networking Web sites such as Facebook and Twitter as business tools. “Tweet” is the term for a post on Twitter.

“Social media can be a vital thing for a business to understand,” said Doug McIsaac, a social-media marketing consultant who organized the event. “The people are there. That’s where they’re spending their time.”

They met at The Carlin, 2501 Montana Ave. While some were the usual suspects in picking up on social trends — like marketing execs and the Billings Chamber of Commerce — others showed just how far social-networking resources have come.

Mike Kilzer is the area manager for Agro-Culture Liquid Fertilizers, a company that sells fertilizer and focuses on sustainable agriculture. He came to learn more about social marketing and said most of his business comes from “face-to-face contact with farmers and ranchers.” While the company doesn’t employ social media as a marketing tool, its draw is tough to ignore.

“So many people are doing their work on the Internet now,” he said. “That’s business, and others are looking at it, too.”

Cathy Grider, marketing officer at Billings Federal Credit Union, said the meetings are great for bouncing ideas off of other professionals.

“Just because a gal is, for example, selling candles, she may have an idea that I can use for the credit union,” she said.

There are more than 300 million active Facebook users worldwide and that number is growing by about 8.3 percent a month. In Montana, there are about 200,000 users, McIsaac said, with roughly 42,000 in the Billings area. As for Twitter, it had between 19 and 25 million users by October.

McIsaac said he wants to expand the meetings and that anybody in Billings is welcome to check it out. He also plans on starting a local chapter of the Social Media Club to provide more information for businesses and is working on the Web site www.billingssocialmediaclub.com.

The next tweetup is 5 p.m. Dec. 16 at The Carlin.