A few years ago, using the Internet to market a small business simply meant to create a presence online with a simple, informational Web site.

Then came the demands of search engine optimization to ensure Google and Yahoo searches yielded top-ranked results for your company. Was your business's Web site chock full of the key search terms that would bring it to the attention of customers?

Today, social media is transforming the small-business marketing landscape. Social media are Web- or mobile-based tools for sharing and discussing information. It's not just for seeing who your high school sweetheart married. Businesses can tap into powerful networking sites and other social media to drive customers to their shops or companies.

If done right, small-business owners might even be able to slash their traditional marketing spending to zero. Writing blogs (short for "Web logs") or ongoing online commentary and using social-networking sites, such as Facebook, MySpace, LinkedIn, Twitter and YouTube, can provide inexpensive but powerful online marketing.

Because it's free, people think it's easy to create a social media presence. But this attitude can lead to missteps. So before you dive headlong into social media, take some time to observe the customs and social norms of these new forms of communications, says David Spark, founder of Spark Media Solutions, a San Francisco-based firm that helps companies tell their story through social media.

"Think of social media as a cocktail party," says David Meerman Scott, author of "The New Rules of Marketing and PR" and "World Wide Rave," books about how to create buzz online. "You don't go into the cocktail party and go into the middle room and scream at the top of your lungs and say, 'Buy my products.' … What works is you have some meaningful conversation first. And that's just how social media works."

If you decide to take the social-networking plunge, here are five ways to harness social media to help your business.

1. Use free sites. Use free online services, such as the mobile short-message site Twitter, and popular networking sites Facebook and MySpace, to post significant news, specials or events. For example, you run a small Italian restaurant with a loyal following. You could create a Twitter account and upload the lunch or dinner specials via "tweets," or short messages of up to 140 characters, daily to customers' smart phones or to other Web sites.

"All you have to do is give a (Twitter) handle and start a conversation. You could put the Twitter handle on the menu or in the restaurant," says Chris Abraham, Abraham Harrison LLC, a Washington, D.C.-based digital public relations agency. Granted, social networking sites are still for early adopters.

"You aren't going to get Aunt Matilda to tweet about the experience she had at dinner," Abraham says.

Abraham considers Twitter one of the easiest ways for a newbie to social media to get started.

"It's more challenging to do Facebook," Abraham says. "You have to create a personal profile, create a page and so on. With Twitter, if you're Joe Smith with Motorcycle Emporium, you don't have to create a page. And you can create Twitter updates via a phone or mobile device easily."

"Don't try to reinvent the wheel," he says. "There are lots of people sold on really expensive solutions, but two of the best investments for reaching out to people and engaging with them are free on Twitter and Facebook."