User profile pages currently indicate the user's location, if they have added one. I've thought recently that it would be convenient to know what time it is for another user. If they mention the time, or I know their location, I can figure it out. But it would be simpler for me if this was calculated by the server and displayed on their page. Obviously, this would only exist if the user set their location (or maybe this could be implemented as a separate field for timezone).
This would be similar to the way ages are automatically calculated and displayed, while not displaying a user's actual birth date or year. I also know that this is done in email notifications I get regarding chat sessions.