Block button(Button located in the Inbox and other folders. Allows users to prevent unwanted e-mail messages from arriving); Block(A permission setting that prevents a person or domain from adding the user to contact lists, seeing the user's status, or sending instant messages to the user)
lock(To prevent users from joining a conference, whether or not they have an invitation); block(To prevent another user from initiating a conversation and from viewing your presence or other information, such as your personal information)
