Zune Pass features, including Mixview playback and channel playlists will be gone after tomorrow but streaming and downloading remain on.
Social aspects of Zune, including messaging and other sharing of songs and playlists are going away August 31, to make way for Xbox Music. In other words, Zune Social is being axed to make room for Xbox Music and the social features included in that package.
This should not be a surprise, since Microsoft served notice Xbox Music would replace Zune Pass back in early June. However, you will need an Xbox LIVE Gold Membership to keep Zune tunes streaming after Xbox Music gets rolling. And, in an example of bad timing, Xbox Music details will be announced soon, leaving a vacuum.