We have been experimenting with ways of making it easier to make comments on articles, but unfortunately this has led to quite a lot of spam comments being generated (but luckily filtered out by our software). The best solution we can think of at the moment is that comments can only be made by registered subscribers. This may seem a bit inconvenient, but don't forget that anyone can register for a free trial for 30 days, which is long enough to make lots of useful and interesting comments, and this can then be cancelled if you decide not to continue (though we hope you stay!). We've switched off Recaptcha at the moment to make it easier to comment when you are a registered subscriber. Also don't forget to login first, otherwise it will tell you that your email address is already registered on the system!