I use my calendar extensively and for a very long time I have been synchronising it between my phone and Google Calendar via Outlook. It has a long history of events on it, some of them private. Now at work they would like me to share my calendar, mostly so they can check availability for meetings and things. This brings to light some deficiencies in the Outlook calendar sharing process.
First, my only options for sharing a calendar involve total secrecy or total access. There is no middle ground where people can see that I am busy but not with what. Second, I can't check my settings by seeing my own calendar through someone else's permissions before I apply them. That would prevent me exposing anything I'd rather keep private and would allow me to do so without inviting a co-worker to check out my calendar just to see if it worked.
Mokalus of Borg
PS - My Google calendar is marked as private by default.
PPS - But that setting does not carry across to Outlook during synchronisation.