SaaS advantage -- in testing?

With all the news about google's chrome, and the release of the nerdy (in a good way :) comic, what really struck me was pages 9 through 11.  Got me and Carl Kessler talking. 

SaaS = testing advantage?  In what environments? 

1. Public data, ok yes billions of web pages in every shape and form ==> thorough testing
2. But private data? Private "user" behavior?

Is there some written/unwritten rules on what is permissible?  We had always looked at privacy and data mining.  What about privacy and "software" testing?

BTW, I am blogging this from 37K ft above the ground, on AA's gogo wifi  Pretty cool, high time.