Note however that editing or adding to an existing post does not reset any ones Alert status for that thread. So if someone had already read your post, they may or may not ever read the edited version. I would therefore recommend that you limit adding to an existing post to the first few minutes after you saved it. If you later remember something that you meant to write, and there are no other posts yet following your last one, just do a new post. If there are two or more posts following the one where you had intended to add something else, on the right edge of the screen just below what you already wrote, click on Reply, which will drop you to the end of the thread and copy your incomplete previous post onto the top of your new post for you. And anyone who was watching that thread will get a new alert if they had already read your original (assuming of course that they have Alerts turned on.