When you change your signature links how does that effect all your old posts? Do they maintain all your old links? Then any new posts will have your new signature links in them?
So if you want to get links with different anchor text then changing your signature links every week or so will not work?
Correct. And also, you're not allowed to drop signatures in the post body. They will be removed so don't even think about it
Well, that would not be so good for Google. They look at the age of links. I believe that is a big factor over time.