As you may have heard, Nature Publishing Group has acquired Scientific American.
The CIC has decided against licensing this product due to the huge price increase NPG levied upon the takeover.
For more on the issues, see the article in Library Journal "More Dismay About Scientific American: CIC Libraries Reject New Site License":
***There have been a few questions concerning the most recent March 2010 online issue of Scientific American on EBSCOhost. Ebsco has been informed of the missing full text and will notify us when there has been any changes or resolution to the issue. The current license with Ebsco Publishing expires May 2010.