This is what it says it is:  click Edit when you want to make changes to your profile or your basic account settings.

• Username - Required.  You'll configure this when you create the account.  Most users will not see this field.
• E-mail address - You can inform the system of email address changes here.  A valid email addres is required.  All system contact (such as password resets) will be sent to the address configured here.
• Password - You may change your password any time you like.  If you forget your password, you can get a reminder here and will be redirected to your account settings when you log in.
• Rich Text Editor settings - These are the settings for the WYSIWYG editor that is featured on most text entry areas site-wide.  The default settings should be acceptable for most users but feel free to experiment, if you wish.
• Glossary indicators - You may choose to suppress the display of Glossary indicators with this option.
• Signature - This is publically displayed at the end of your comments.  You may include what you like here.
• Picture - A User Image is what is commonly referred to as an Avatar.  This is, for all intents and purposes, your face on this site and will be featured along with everything you post, including comments.  If you choose to change your picture, simply make sure the "Delete picture" box is checked, "Browse" for a new one (this will open your computer's file browser) and hit "Save."
  Although this is stated plainly on the profile page, it warrants repeating:  A picture may be worth a thousand words and it is often best to choose them wisely!
• Contact settings - Pretty self-explanatory (with good help text on the page), this dis/allows other users to contact you.  Privileged Users, such as Site Architects, may always contact you by the email address you provide.  As stated in the help text, your e-mail address is not exposed by the system.
• Locale settings - This allows you inform the system the time zone in which you live.