Your Userspace is a personal space for you. Userpages are any page bearing "User:" in it's title.
On your userspace, you can write about yourself, your interests, your hobbies and anything else you want, but also about your interest in CLAMP, CardCaptor Sakura and any other anime you watch. You can access this page once you have done registering and click on your name. You should always link back to this page whenever you make a post on any of the discussion pages on the wiki by posting using the signature with timestamp option (which is basically ~~~~). You can decorate your userpage with Userboxes. You are also free to make your own! It's easy! Just copy the code for another userbox and change it to suit your own one!
For more help, please see Wikia Help on Userpages.