My profile says it's only 58% completed, how do I complete it?  Also, what is the value to me of completing it ?

If you click on "My Home" and then on "Edit Profile" you will see a Profile Completion status bar on the right side of the page near the top.  Underneath it is link labeled "What's Missing".  If you position the pointer over that link, a drop down box will appear with a list of items that are missing.  

There are a number of benefits to you in completing your Profile.  First and foremost, PRESENT Diabetes is a networking site modeled after Facebook, but solely for diabetes care professionals.  It's designed to get you in touch with other diabetes care professionals that share a common background, training, experiences and interests with you. It does this by offering you colleague matches. The more information that you add about yourself to your Profile, the better the matches become.  When you accept a colleague match, you and your colleague share professional experiences and learn from one another in a number of ways.  The site also monitors your use of the site over time, and based on your particular use of the site, more accurately suggests colleague matches for you..