I know I can ignore friend requests that are unwanted but what about messages? I also would like to know if my address is public on the site.
I just see your question now, sorry for a late reply.
You can avoid unwanted messages by setting your page to private. The disadvantage of a private page is that possibly new nice connections will not find you easily. And that other people (than your friends) cannot enjoy the photos and blogs you post of your received and sent mail art.
The advantage of course is that you alone can choose who can see your profile page.
Every IUOMA member is free to choose to have a public or a private page, so feel free to do what feels best to you.
You can delete unwanted messages from your profile page by putting the mouse cursor above of the message. Then you see an 'x' top right of the message, and by clicking the x you delete the message.
As far as I can see your address is seen: the name of your street in your profile information (in the center column, scrolling down), and the name of the city under your avatar on the left.