When CBS News went public last year with what it thought was evidence that President Bush had shirked his National Guard duty, it seemed that no amount of White House spin could keep a lid on the scandal. But a group of largely nameless so-called bloggers took up his defence, posting online dispatches questioning the authenticity of documents CBS used for its story. The rest, of course, is history. Bush was re-elected; several CBS employees were shown the door.

In less than half an hour, and for free, you, too, can create your own online media empire and affect the world. You won't need to cut a deal with Donald Trump or Rupert Murdoch. You can just set up a weblog and start publishing your ideas and opinions. With blogs, you're free to explore almost any subject; journalists use them to scoop each other, politicos argue conspiracy theories, teenagers express angst and sports fans vent frustrations.

Even if you're not particularly tech-savvy, today's free blog-hosting services make it simple to publish your daily musings.

  • What's a blog, anyway? Think of a blog as either an online diary or a never-ending newspaper column, full of links to online material that stimulates your brain or makes you laugh. They may hold breaking news, wry commentary or everyday observations, plus comments from other readers.

    While politics and technology inspire many bloggers, web journals connect almost any group of like-minded people, from gadget enthusiasts, to Harry Potter devotees, to time-starved mums. See Yahoo's blog directory for more. Some people use a picture-filled blog to keep family and friends up to date on big events, such as a wedding or a new baby. Companies use blogs to communicate with customers. Your blog's purpose – and cleverness quotient – is entirely up to you.

  • How do I get started? If you want to take the cheap and easy route, use a free hosting service, such as Blogger.com or MSN Spaces. These services now make it easy to set up a basic blog. You register, pick a template for your blog's appearance, enter your prose, and click to publish. Once you're set up, you just keep making new entries, which always appear at the top of the web page.

  • Want more control? You can also use Blogger.com's creation tools and host the blog on your own web server. For a step-by-step guide on how to do this, visit PCWorld.com. People who want maximum design flexibility typically add a blog to their website using a software program such as Movable Type.

  • Will people pay to read my blog? No. Some prominent writers make money by selling advertising space, but you'll have to have a large social network of acquaintances to generate enough web traffic to earn a living selling ads. Your blog will probably be more about personal satisfaction than profit.

    Still, a blog that creates buzz with a professional audience could earn you networking opportunities, speaking engagements and the like. Bloggers often link their posts to others they like and/or respect. Some people even meet Mr or Ms Right.

  • What are the unofficial rules of blogging? Blog readers can be a demanding bunch, and many don’t have long attention spans. Post new entries often – ideally every day – and don't drone on. Posts don't have to be long to be engaging.

    As a matter of etiquette, make sure entries are spell-checked. You'll also have to decide whether to allow people to post comments regarding your entries. Some bloggers love the free-wheeling dialogue that flows in the public comments space, likening it to the democratisation of the media. But other writers decide they can do without this kind of unchecked feedback. If you do allow comments, develop a thick skin and don't feel you have to respond to every criticism.

  • Should I worry about privacy? Yes. Some groups, including the Electronic Frontier Foundation, recommend blogging anonymously. See the group's recently released tipsheet on blogs and privacy. But even if you want to tout your name in bright lights online, follow some basic privacy rules.

    First, don't reveal personal information in your blog that others could use to find out even more personal information about you. Don't dish about confidential work matters, or salary info, unless you're trying to get fired. And if you're going to start a blog discussion about nightmarish bosses, Murphy's Blog Law says your boss will find it.

  • Can my employer fire me for criticising the company in a blog? Maybe. Your boss doesn't necessarily have to put up with your ramblings, especially if you use a company PC to monitor or manage your blog. That said, some companies encourage blogging as a way for employees to engage customers, partners and so on. Several, such as IBM, have issued guidelines for employees to follow, so everyone understands the rules.

    In general, unless you're at a company that encourages blogging as a way to communicate, such as Sun Microsystems, don't blog at work. Anything you create on an employer's PC is fair game for monitoring.

    If you're going to talk business on a blog, make it clear you're not speaking for the entire company. And remember, if you keep a racy or controversial blog, potential future employers may find it when they do a web search for information about you (and many will).

  • Can I blog while away from home or travelling? Yes. Many people create travel diaries using blogs. You can write and post entries anywhere you can access the web. Some services, such as MSN Spaces, now even let you post entries via cell phone.

  • Can I create a members-only blog? Yes. Services such as LiveJournal and MSN Spaces let you password-protect your blog (or certain blog entries) so only a group of specified family members or friends can get in. This makes particular sense if you're writing about your kids or a family event; the whole world doesn't need to know the details.

    Another way to increase your privacy quotient: keep your blog out of Google's grasp if you don't want it popping up when other people do web searches. Blogger.com (which Google owns) gives you this option at set-up time. Or you can use a special file called the Robots Text File to keep your blog out of Google: The EFF recommends using the free Robots Text File Generator tool at Web Tool Central to do this.

    Most of all, have fun and be creative. Conceptually, blogs are fairly simple. But use your imagination, and they can be more than online diaries. Need to collaborate on a project? Use a password-protected blog to share notes and updates. Going to be away from home and need to get in touch with several people? Post your whereabouts online along with requests, instructions, impressions and so on. And who knows, maybe your witty insights will soon make you the centre of attention on the web.