Whether you are a stamp collector, squash fanatic or hip-hop fan, a blog or personal website is a great way to share your interest. It can also be an easy source of cash. If you are publishing content and not hosting advertising space, you are missing out on a small but hassle-free second income.

The easiest way to make money from your site is to sign up with a free advertising server. Google’s AdSense, at www.google.co.uk/adsense, is the leading programme and is compatible with pages hosted by most providers.

Once your site is approved for AdSense, Google will deliver targeted advertising to complement your content. Each time a visitor clicks on an advertisment, the advertiser pays Google commission. Google then pays you a cut — an undisclosed percentage, from a few pence to several pounds. Financial advertising pays well, so Times Money readers blogging on savings stress or mortgage moans will be off to a good start.

David Johnson, Google’s AdSense manager for Europe, says: “It is a great way to supplement your income from a hobby. There is no contract to sign so you have nothing to lose.”

Set-up is straightforward and you can control the amount of advertising on your site and decide whether to display text only or text and picture advertisements. You can also customise the advertisements — changing the colour of ad boxes to blend in with, contrast or complement your background.

Your advertising income depends on a complex range of factors. A high-quality niche site, for instance, might attract less traffic than a more mainstream site. But visitors will be more likely to click on the ads. Mr Johnson says that the key is to maximise traffic to your site by delivering the best content possible and updating it regularly.

James, 30, works in marketing in North London and is the secretive author of the Alternative Energy Blog. He writes an average of one entry a month and has built a global following, with 7,000 subscribers. His advertising income varies but he says that it is enough to pay for lunch every day. “We’re talking more than Burger King and a lot less than The Ivy,” he says. Whatever that means, it is a good return on a few hours work each month.

At the moment there are 11 unobtrusive text advertisements on James’s site — a blog hosted free by Blogger.com. All of them are content-relevant. Most link to sites selling alternative energy technology and pay about 10p a click. James says: “They actually offer something useful to my readers — it’s a service.”

If you are not publishing online already, free blog hosting with the likes of Blogger.com and website hosting with sites such as Google Pages (www.pages.google.com) mean that you could soon earn cash for your thoughts.

For more on consumer affairs visit www.timesonline.co.uk/consumeraffairs