The Wall is a space on each user's profile page that allows friends to post messages for the user to see. One user's wall is visible to anyone with the ability to see their full profile, and different users' wall posts show up in an individual's News Feed. Many users use their friend's walls for leaving short, temporal notes. More private discourse is saved for Messages, which are sent to a person's Inbox, and are visible only to the sender and recipient(s) of the Message, much like email.
Who can see my Wall?Edit
By default, your Wall is visible to anyone who can see your profile. You can restrict who your Wall is visible to, or turn it off entirely, by going to the "Profile" section of the Privacy page.
Can I delete entries on my Wall?Edit
Yes, you can delete any comment on your own Wall. The option is available under the posting.
But keep in mind that it's considered very rude to delete friends' wall posts