If you have a Google Profile and you have it set to private, you aren't using the service correctly apparently. Google doesn’t want your stinkin' profile on its servers if you won't share with others. In fact, Google is going so far as to say if you don’t want to share your profile, delete it. If you don't delete it and won't share, Google will delete it for you on August 1. In a nutshell if you use a Google profile its share or go home.
Google notes that the point of Google Profiles is to allow you to manage your online identity and right now almost all of the profiles are public. The search giant thinks that public is best after all and therefore all profiles are required to be public. Google points out that only the full name and gender are required information on the profile and any other info can be removed or edited.
The thing that I see here is sort of a precedent that Google is setting and I see some possible ramifications. What if this is a sort of test to see how people react to being made to share or not use the service. What if the next part of this is a roll out of that long anticipated Google social network with the caveat that what you put on the network must be public. What if Facebook decided to follow suit? Faced with share or go home, most people would keep sharing and using the service and it would certainly make generating revenue off a social network easier.