When I get to 50 posts and I am able to put links in my signature... Does this get applied to all my previous posts as well?
Check the FAQ for signature guidelines. It sounds to me like you have misread. I believe signature is only active from beginning with first post after signature is added.
It's not retroactive to your previous posts, since you can choose to have a signature on a per post basis.
Thanks....Its good to know that the master of the Punyverse still answers questions on such a large forum...