Option to hide "Last Online" in forum

[VP8M8]

If you reply to a thread you're probably going to stay logged in in case you 
get a reply back. In the case that you don't end up posting anything else for 
the day, your last online status could become an indicator of when you usually 
stop browsing. Also the general idea of private activity tracking leaves a bad 
taste in my mouth. Yes, you could log in and out each time you reply but I 
figured a forum setting would be easier if enough people are also privacy 
minded.