Google registered two brand new domains on April 17th: googlesubscribed.com/net/org/info and googlesubscribedlinks.com/net/org/info. Google rarely uses domains they register, but they almost always turn out to be a good indication of future functionality.
The question here is what Google Subscribed or Google Subscribed Links actually is. There are a few things it could mean -- but I am leaning towards it being the name for the link bar found on some Google services like Gmail and Google Calendar. The same link bar that my Greasemonkey script patches up to make it function like it should.
Before Google Calendar was released, someone found a link to the login screen for the service through an innocent looking page that let you add or remove links from that blue bar -- this is exactly what I think Google Subscribed Links will be. The current bar is probably just temporary until this subscribed links service is finally launched.