I saw a really good example of how to do an online registration form properly today. I'm talking about the form you fill out to register for a website, usually for discussion forums.
You might know the ones, you go to a forum to realize you have to register just to view it, and then you are bombarded with questions, only a few of which are compulsory.
For example, you might get asked for a username, email address and password - these are compulsory, but at the same time, there is input field after input field asking you for all of your personal details, birthday, interests, do you have a website, whats your msn/aim/icq/skype/xfire/insertIMProgramhere - it's okay though, you don't have to put these in.
These types of sites annoy me, I, like most users, like things done quickly and pain free, it's annoying enough that you made me sign up to your website and then get a verification email from my inbox just to see if there is any active discussion, don't make things worse by making me look from text box to text box seeing if there is a * character next to it. I want to do the minimum amount of thinking, I'm not going to surrender my life story to you if I don't even know what the forums are like!
Sure, maybe later on, when I've decided to actively participate in your community, then I'll go to edit my profile and add in some details I'd like to share. But in the mean time, just show me what I need to do - make me think well maybe this isn't so much of a hassle after all, rather than dammit do I have to put all that in?
Here is the example of what I was talking about, well done Babstats.com: