For some people, the ability to share items and follow other people is one of the major attractions of Google Reader. But if you prefer to fly solo in a cleaner interface and want a way to switch off all the social features, you can do that with a little URL hacking.
After reloading, your Reader screen will have shed the 'People you follow' section. Hit the post for details on how to switch the feature back on if you change your mind. For an even more minimalist approach to Google Reader, check out Helvetireader, which is also an option in the Better GReader extension.
Disable Google Reader's Social Features [Google Operating System]