We often have to ask people to confirm an action. The usual text is:
"Are you sure that you want to _________?"
Are there any shorter but clear ways of asking this?
The value of confirmation messages is to give user a chance to stop themselves from doing a potentially wrong action on the potentially wrong thing under the potentially wrong conditions, so try to make the message only include the action, object, and conditions (if applicable). Thus, the most terse message would be the form:
The confirming button should be labeled with [action].
The “are you sure you want to” or “do you want to” text is more conversational, which some users may like, but given users’ tendency to avoid reading as much as possible, I think there is something to be said having only the most critical information.
However, I wouldn't go any terser than above. For example, I wouldn't make the second bullet simply "Disconnect?" (let's say that's what the user actually commanded). The user may have meant to disconnect from something else, so they'll confirm when they shouldn't. Or they may be unaware of the condition or implications (i.e., that it will cancel an upload), so again they'll confirm when they shouldn't.
Taking inspirations from others
When I click on 'About Google Chrome' on settings tools menu, it shows that updates are available and give a button to update.
iPhone HTML5 database delete
When I go to Settings -> Safari -> Databases, it shows list of databases with a 'Edit button' at the top. On clicking edit button, it shows minus button "-". When you click on 'Minus' button, it slides 'Delete' button from the right to ask users confirmation.
facebook app submission confirmation
It shows summary of the app right above the 'App detail' page and give 'Confirm Submission' button
Sending mail without subject in gmail
It shows up dialog prompt "Send mail without subject?". Once you click on 'Yes' it sends the email.
These are some of the different context where user's confirmation is taken differently than simply showing the confirmation prompt.