Blogheads have discovered a better reason. They write because they know that in theory their words can reach any of the 600 million readers who currently log on to the net. When you can cast your pearls before that many swine, who cares about money?

Blogheads, of course, churn out weblogs (or blogs). If you’ve recently returned from some other planet, I’d better explain that a blog - like a copy of the Da Vinci Code, an unusual allergy or an iPod - has been the must-have item of recent months.

A blog is simply your own small corner of the net where you can post text, images, animation and hotlinks. In fact, to all intents and purposes, it’s nothing more exciting than ye olde web page - with one important exception: instead of having to master HTML or twiddle with the software that does it for you, it’s as easy to maintain a blog as it is to send email. It takes very little effort to update it every day or, indeed, every hour - which the most fanatical bloggers do. It gives them the sense that they are keeping in continuous contact with the whole wide world. And, believe me, that beats a 10p text to the pal whose ear you usually bend.

There are now at least five million bloggers but even conservative estimates reckon that the number doubles every five and a half months. Do the sums and you’ll see that it won’t be long before they will have colonised every available gigabyte of cyberspace. To get a taste of what it’s all about try blogwise.com, bloggingbrits.co.uk, or any of the many search engines dedicated to keeping track of this latest, and strangest, literary phenomenon.

Since every blog worth its salt hosts links to similar blogs, once you’ve found one that takes your fancy, you’ll soon find yourself bookmarking hundreds of others - in fact, far too many to visit regularly. However, once you’ve mastered RSS (Really Simple Syndication), which isn’t nearly as daunting as it first appears, you’ll never have to go to the trouble of visiting your chosen blogs as any new content is automatically delivered to your desktop.

The compulsion to blog seems to have gripped everyone from babes-in-arms, who blog before they can burp, to Belle de Jour, a London call girl (allegedly) whose weblogs, now collected between hardcovers, are currently in Waterstone’s bestseller list. Celebrities, leading politicians and Boris Johnson blog. And a few bloggers have been on the frontline of history. The Baghdad Blogger, for example, filed clandestine reports from the heart of his war-torn city; and it’s bloggers who provided the most moving, eye-witness accounts of the tsunami.

Most blogs, however, are just ordinary people’s sincere attempts to tell it like it is. They write about their worries and aspirations or record the minutiae of their lives. Because they don’t have to please an editor or a teacher, they just let the words pour out: “typing aloud” as one blogger calls it.

This doesn’t make for great literature, but it is compelling reading for those of us who can’t resist eavesdropping in cafes or can’t pass an uncurtained window without taking a peep. Forget about reality television or the modern novel - if you want an authentic picture of how people are getting on with their lives, spend a few hours nosing around the “blogosphere”.

You’ll be amazed both by the sheer number of teenage bloggers (estimated to be in the millions) and by the brow-furrowed earnestness they bring to their writing. An American survey of blogs created by 13 to 19-year-olds reveals kids routinely churn out 2,000 words or more when they are in blogging mode. It’s hard to believe that they are are quite as enthusiastic about writing when they’re in school.

It’s not surprising, then, that wily teachers, especially in the States, are busily exploring how to use blogs in the classroom. Visit some of the sites shortlisted for an Edublog Award (at http:incsub.orgawards index.php) for a crash course on how blogging can be used in a range of activities across the curriculum. And it’s not limited to secondary school.

At www. hangletonweblogs.org, you’ll find Year 4 pupils in a Brighton school blogging with such panache that last year they won themselves a New Statesman New Media Award.

Weblogs could revolutionise teaching in other ways. By building in a password, you can restrict who visits your blog. You can also enable registered users to contribute to the same blog. So, in effect, it can serve many of the functions of a school intranet - without the need for sophisticated software or technical support. Worksheets, homework assignments, weblinks, quizzes and suchlike can go online with the minimum of fuss. If you want feedback from pupils, give them the password and they can chip in their digital penny’s worth.

There’s only one way to find out if blogging really is that easy - set up your own weblog. Many providers will host it for you without making any charge. If you’re a Hotmail fan, use Microsoft’s service at http:spaces.msn.com. The rest of us are happy with Google’s blogger.com.

In less than 10 minutes you’ll be a bona fide bloghead. As you post your first paragraphs of purple prose, don’t be put off by the whirring sound.

That’s only Dr Johnson spinning in his grave.