I know that we're still selling stuff, but our hope is to do something good along the way, and a world with more privacy information is surely a better one :)
First it's in Google's terms, have a quick look here there's an interesting write up regarding this topic that covers it better than I could here in this short amount of time: http://searchengineland.com/how-many-google-privacy-policies...
Secondly GA collects personal data from your users which in most legislations means that you need to inform users about that fact (most notoriously Europe).