» Roelof Pieter:

“[...] I think it works like this: When I create a note, the group or persons in TO or CC get a copy of this sent to their account (like e-mail). Apart from sending it to these persons pump also saves the note on my account (on the server I have an account on). Posting my my note to "public" means it will a.) be "sent" to my followers and b.) the saved copy can be read by visitors (or crawlers) [...]”

Yes, all that is quite correct =)