Currently for people to edit what is in their scratchpads they have to go to edit their user information, and then go elsewhere for the scratchpad. I've noticed that this process causes considerable confusion and causes experienced people to have to give a complex little explanation when trying to help newbies in chatter.
My suggestion is that from within your own scratchpad you should have a textbox where you can edit the contents of the scratchpad and change whether or not it is public. Just like how we can edit our own posts.
That would allow us when dealing with a newbie to just type in Can you put some code [pad://your name] and let us see it? Much easier to describe, much easier to do, and much more intuitive than the current process.
(Note: this post was inspired by a comment from tye in chatter about how useless it is to tell people to put something in their scratchpad, and link to that scratchpad. That uselessness struck me as a sign of a bad UI...)