If you do not, you will have to type in your username and password every time you want to post, and every time you visit a private forum. Only registered users can edit their posts. To edit or delete your posts, just click the edit icon by your post. When you make modifications to your posts, a note will appear at the bottom of the post telling other users that you have edited your post. Moderators and administrators can also edit your messages but this note will not appear.
Signatures are only available to registered users.
When you post, there is an option to use your signature. If you want to turn the signature off in the future, you can come back and edit your post. If you have specified a signature in your profile, the box will be automatically ticked for you. You can search any forum that you have permission to search - you will not be allowed to search through private forums unless the administrator has given your the necessary security rights to do so. This will give you a form where you can fill in your registered email address, and your password will be emailed to you straight away.