martinibuster - 9:10 am on Jun 7, 2010 (gmt 0)
It is a problem if the registration process is difficult. One way to make it easier is to put a human challenge, like asking them to do a simple addition problem. This kind of challenge is effective against bots and is less hassle than a captcha. If you want to make it easier to register you can also skip the requirement for them to confirm their membership.