Not that I'm keeping track, but I've noticed my message count is stuck at 918, while I've been posting numerous messages since yesterday. How come? Just curious...
[edit] and now it has changed to 919..oh well...nevermind...
Depends on the 'existing thread'; as others have pointed out, if you post in PRSI (and one or two others) this will have no effect on your message out, as posts in PRSI are not counted towards your total number of posts.