I've made some changes in my Google Reader settings. My "starred" feed is no longer public and instead, I created my public "shared" feed (notice "shared" / "starred" - two different things).
What does it mean?
If you want to read feed of interesting news I found (something like Stumbleupon, which I no longer use), just bookmark this page or use RSS feed which is included in it.
If you were already subscribed to my starred Reader items or to my StumbleUpon feed, delete these subscriptions (they are no longer accessible / updated) and replace them with the new one (see the paragraph above).
Sorry about the inconvenience but "shared" feed wasn't available when I started using Google Reader and I now have better use for "starred" feed.