Social networks – Facebook, twitter, chinaren, sina, sohu, douban, myspace
Communication tools – Google phone, Black Berry, Iphone, Ipad, Skype, Google Talk, regular phones.
Different Email accounts – Yahoo, Google, Hotmail, outlook, Lotus Notes
Specialized calendar tools – CRM, Golf, Doctors, school calendar, girl scout, special accounts, etc.
There are at least 10 places that address, email, phone numbers, and calendar information need to synced. Maybe a personal MDM is the answer.