Here's some information that the website doesn't automatically give you.  

Polls are completely anonymous.  Nobody can see who gave which answer, and nobody can see who responded and who didn’t.  The Poll module is a box on the right side of the Home Page. 

Surveys are confidential, meaning only website administrators have access to each Survey participant’s name with the participant’s answer.  We cannot make the Surveys anonymous.  Surveys are open to administrators because they're used for such questions as “Do you want chicken or veggies at the reunion?”  MacMemories and Guest Classes are the only Surveys we’ve had so far. 

Administrators can see your last login date.  Administrators have access to various user statistics, including a list of members with each member’s last login date.  This is another feature that we cannot make anonymous.  All of the other statistics are anonymous. 

Nobody can see the password that you enter.  So no administrator can log in as you and read your messages, for example.