The default privacy for new UCSC Google Sites was changed from a
very "open" model to a "private by default, but can be set to open"
model. This change does NOT affect existing Google sites, just new sites created after May 21, 2013.
To check and update the privacy setting for your Google Site, navigate
to your UCSC Google Site, click the "More" button, select "Sharing and
Permissions", where you can adjust the site privacy in the "Who has
access" box.
Please let me know if you have any questions at lbono@ucsc.edu.