After Googling for what seems like hours, I finally came across a decent article that explained how HubPages work.
Have decided to sign up, and will use HubPages to test out my theory of writing about coping with debt in a recession (something I know quite a bit about). Hubpages shares ad revenue with members (60% to the member and 40% to them), but I haven't yet figured out whether I have to put the ads on there myself or whether they do.
Anyway for the moment I will concentrate on building my "hub".
Update 10th March 2009: OK, have produced my very first hubpage - Do It Yourself Debt Management.
Have also found out how they do the ad revenue - basically you have to sign up with Google Adsense or Kontera, and tell HubPages your ad ID - they then place the ads on your page and split the revenue.
Have decided to try Kontera only for the moment. Kontera produce little text-links in the text of your article. Payment is pay-per-click and they payout by Paypal 30 days after you reach $100 in your account.
Have decided to put Kontera on this blog too, to see how it all works out.