Thanks for all the feedback and opinions on this. We're reading all
your comments, though clearly we can't respond to each one
individually. I'd like to address a few of the most common concerns,
though.
* Your friends will not be able to see all of your subscriptions, but
only individual items that you have explicitly marked as "shared."
* Your friends list doesn't necessarily include everyone in your Gmail
address book. It is limited to people you have chatted with on Google
Talk and who also use Google Reader.
* The "share" feature was always intended to imply some amount of
publicity. That's why we used the term "share" and had shared items
marked as public by default on the Settings > Tags page.
* There's a "clear your shared items" link on the Settings > Friends
page if you urgently need to remove the items you've shared in the
past.
* It is still possible (as before) to share specific tags, or your
starred items, independently of your shared items feed. This is a good
alternative for people who have more specific uses for this feature
than the general concept of "sharing." Details on how to do this can
be found in the help center:
http://www.google.com/support/reader/bin/answer.py?answer=70656