Until recently, if you had some expert knowledge in a specific area of business, you kept it pretty secret and only shared your hard-earned expertise with paying customers.

The Internet has changed that. Sites like Meetup.com, Flickr.com, Facebook.com, LinkedIn.com and Slideshare.com allow members to create interest groups around a niche or a topic and freely share their expertise.

This may not make much sense, at least initially. Why would you give away something you can get paid for? Well, there’s a new generation of Web-savvy customers for whom this makes total sense, and you need to pay attention.

Here’s how it works: I want to find an expert in widgets in my area, and I want to make sure the person I work with really knows what’s happening in the widget world. I want to be sure my work will be done expertly, and since I don’t know much about widgets, I need a way to “test” potential suppliers.

What’s more, maybe I don’t really trust widget company sales people. Maybe I’ve been over-promised and burned in the past.

So what do I do? I Google “Northumberland widgets” and look for every reference I can find that gives me the information I’m looking for. When I find a Facebook group or a Meetup in my area that’s packed with widget users, I know I can ask them all my questions and be sure of getting the information I need to make a good decision.

I find a series of PowerPoint presentations on SlideShare made by a particular widget company that tell me how to buy and maintain widgets, what to look out for when assessing competitive bids, and ways to lower my widget operating costs. Now I have concrete examples of what they know that can help me.

And when I look up the company principles on LinkedIn, I’m impressed by their professional history, and I join some of the groups they are part of.

So whether your business is selling washing machine parts or kite making supplies, you can start a group that’s attractive to people interested in those activities. Think it might lead to some business opportunities?