I see where we can have Date and Time Stamps

I see where we can have Date and Time Stamps in the chatroom. What time zone are those in? Is it based on the person's local computer? Is it based on the Wordpress Time zone setting? Is it based on my server? For example... if I am in New York and it's 12am, will it say 9pm for someone in Los Angeles (PST Time which is 3 hours behind New York EST) or will it say 12am?