I dislike the idea of running a server. Either it is

• a server you rent (high responsibility, legal accountability)
• on your LAN (too much private data, too dangerous, see above)

I dislike Google more and more. Since a few years I am wishing there would be some initiative by privacy aware people, who offer something similar like Google's docs, cal, mail, picasa, +, etc. but on a commercial, or semi-commercial (non-profit) base. I would be willing to shell out a 120€/year for a liberal concept, that even has an API.