I don't know if people know this but:

When you are starting a new topic and use reply off another
thread but erase the old subject. The new subject is still listed under the thread you erased in Gmail and other email
programs. If you want the most exposure to your new topic 
be sure to avoid using the reply on an existing subject. 
I don't read every thread and have missed emails because of
this. Just an FYI for those who dont know. 

Bill