Post scriptum
I’m still old school in the sense that I don’t write emails all in lower case and my IM’s and text messages are written in real words that you can find in the dictionary. I also have the practice of adding “PS” (or post scriptum) to my emails whenever there are ideas I want to add after the train of thought ceases. The “PS” surely made more sense when people used to write letters with ink and paper (and believe me I’ve done that a lot). Some of you will remember how was hard to insert an idea after writing the entire letter.
Regardless I think the PS is still applicable and sometimes it’s important to stress that something was thought after the process of writing an entire email.
PS: From the Wikipedia I found that writing “P.S.” was “wildly popular in the 1770s and was in several of the letters Paul Revere delivered on his famous rides.”