On 2013-05-08 10:09 (GMT+0200) Pierre-Yves Chibon composed:
you are replying to a 4 days old email on a thread that is no longer active?
A: The thread was started on a Friday night.
B: Some people don't get to read mail every day, or more than a few or less times a week.
A + B = perfectly justified timing of reply.