Gmail Sender time zone lab feature helps you to see the email sender is reachable or not by simply enabling this new lab feature.
So this is the example Gmail blog is giving out
"Let's say your girlfriend sends you an angry email. It's mostly about how you behaved at the party last night and then left for a business trip without saying goodbye. You read it from the other side of the globe, jet-lagged after a 12 hour flight. You want to call and sort things out, but forget that it's now almost 3:00 am her time. After waking her up, things only get worse."
Do you think this lab feature is useful? If so better hurry up and enable it and avoid annoying phone calls to people at the other end.
