If you remember about a month ago, Google removed a feature in Google Pages that let users create multiple different websites with different addresses. They just brought back the feature, so you can once again create up to five websites with different URL's.
Now, do you remember when Google first launched Google Pages, there were many people who were complaining their website URL was an easy target for spam bots looking for email addresses. For example, my site http://gootch2.googlepages.com basically reveals my email address (gootch2 at gmail.com) to spam bots. A simple search for "inurl:googlepages.com" on Google gives me more than 500,000 results.
With the new updates to Google Pages, you can now also hide your primary website in the site settings --effectively hiding your email address from spam bots.