Sometimes when I post or send PM's my signature does not show up on the bottom. Most of the time the signature does show up. Is this normal, is there a reason why it's that way, or do I have a setting wrong?

Also, if I change my signature, will it change for all previous posts & PM's already containing my old signature?

Pretty sure the sigs show up in your first post in
a thread and then if you repost to that same thread,
it doesn't show.

What Xena said but I think it's actually first post on a page. They are shut off on subsequant posts to improve performance from the server end as far as database access goes.

Gazza