The NY Times reports that when you subscribe to a channel on YouTube, the Google-owned video sharing site publicly broadcasts this fact by putting your user information on that channel’s page for anyone to see:
Google’s video site lets you subscribe to a “channel” — a collection of videos from one person or company — so you can get reminders about new clips from sources that interest you. When you do this, your user name and photo are usually listed on the page of the channel you are subscribing to. And there is no way for you to keep your subscription private.
That means that if you have some reason to want to follow videos from channels like Youth Suicide/Domestic Violence Health, ProstateCancerMD , Bankruptcy Attorneys or Best Resumes of New York, anyone in the world could find out.
YouTube never explains this when you sign up for an account or use the subscription feature. There are some other aspects of using YouTube’s site that also publish its users’ viewing choices without properly explaining what is happening.
Saul Hansell describes the implications of this:
As I use YouTube, and I don’t think I’m alone, I use the subscription and favorites features not to share my tastes but simply as bookmarks to keep track of things I may want to look at again.
This can be seen in how YouTube creates a channel — essentially a profile page — for all users when they establish an account or sign in using their Google account. This page, which is open to anyone on the Internet, by default, lists the other channels you subscribe to, the videos you mark as favorites and the playlists you have made. Users can remove these sections from their channels, using a rather complex page buried in the site’s options.
There is no requirement that you use your real name in your YouTube user ID or post any identifiable information on this page. But users may well leave clues to their identities on their profiles without knowing how they may be used.
If this doesn’t upset you already, consider YouTube’s initial response:
Chris Dale, a YouTube spokesman, said, “We’ve never had a complaint about this issue, but we’ll look into it.” Mr. Dale declined, however, to explain why the site is designed this way and whether this matter is an oversight or whether it believes that these viewing choices are facts that all its users would like to share.
So, what can we take from this? Either YouTube doesn’t realize what kind of personal viewing data they’re making public without giving users proper notice or the ability to easily opt out, or they simply assume everyone wants to share all of their viewing interests with the entire universe, and since no one has complained, there must not be a problem.
Unbelievable.
MichaelZimmer.org 
To Google’s credit, this one struck me more as a “lazy programmer” problem than anything nefarious. The “hide subscribed groups” is probably a feature ticket sitting under piles of other more important stuff. Hopefully this will give them a little kick in the pants, because these are very valid criticisms.