"People you follow will see that you are following them and may display their followers on their public profile."
That means that regardless of how you arrange your privacy settings, you will be visible to the Buzzosphere.
Since your profile name is also your email address, that means that your email address ends up being visible to the world. Gmail does a good job of protecting us from spam, but there are many people who might not want their email address to be publicly known. Google's solution for that is to give the possibility of using a long unfriendly number. Mine is 117130852944864714190. Recently, the long unfriendly number became also the default for Picasaweb.
It would be nicer if Google could give the possibility of profile nicknames, just like many other services. That would give us 3 options: a) to use the email identifier b) the long unfriendly number and c) a nickname.