Silicon Valley Insider came up with this wonderful sensationalist FUD piece: WARNING: Google Buzz has a huge privacy flaw!
Please.
They recommend shutting off Buzz completely, or un-following your automagically-generated "friends" that Google "chose" for you (i.e. other Google Profiles that you exchange e-mail, Google Reader, or GTalk with). This isn't really a Buzz issue at all, though. It's been a "problem" since Google Profiles came out, it's just a lot more intuitive to see who people interact with in Google Buzz, since it's built into GMail directly now.
UPDATE: It looks like contact sharing *IS* enabled only once you sign up for Buzz. So, shame on Google? If you don't sign up for Buzz, these options won't even show up (and neither will your contacts on your Google Profile) - Thanks, Genesiswave, for pointing this out.
Or, you could think rationally, and simply un-check the option to make public the list of people you interact with. Imagine that?
So, take a deep breath, log in to some google service, then click this link to edit your profile if you're really that worried. Again, this option is only displayed once you opted in to Google Buzz.
Now, the followers/following links are only visible to myself. I verified this through Google Buzz and by looking at my profile page from a different google account.