CHICAGO ( TheStreet) -- With blogs, Twitter and Facebook, everyone can be a critic. While that's good for free speech, it's a double-edged sword for business owners. Compliments and complaints can now broadcast around the world and bad reviews can linger online for months or even years.That's why it's critical to keep tabs on what people are saying about your business online. Large companies can afford to have in-house "online reputation managers" scrolling the Internet, checking for any mentions of their business. But for small businesses, such vigilance might seem difficult, time-consuming and expensive. However, it's easier and cheaper than you might think. And it's just as important for small companies to be mindful of their online image as it is for multinational corporations. When you have a smaller pool of customers, a few disparaging comments can have a proportionately larger impact. Herbert Tabin and Craig Agranoff, reputation-management consultants and co-authors of the recent book Do It Yourself Online Reputation Management, say small-business owners often fail to consider how they're being perceived online until it's too late. "One detractor with an Internet connection can be your enemy," says Tabin. "Either you control what's said about your business or other people will." The first and most basic step is to own the domain names associated with your company. That means not only your business's Web site, but any variations of the name that could be used to disparage your company. Type "www.walmartsucks.com" into a search engine and you'll see that the domain has been reserved, possibly by Wal-Mart ( WMT), to prevent someone from creating a critical Web site. Another way to counteract negative feedback is to increase the amount of positive news about your business. Get involved in community or charity events, and then let the public know by updating your site or sending a message through Twitter or Facebook. "Most people don't go beyond the second page of Google ( GOOG) search results," says Tabin. Your goal is to make sure only positive news shows up on those first two pages. You should try to respond to negative posts quickly. To find out what's being said about your business online, sign up for Google Alerts, a free service that lets you know when your business' name appears online.