iOS6 bookmark, sync problems

I installed iOS6 in my iPad 2 and immediately faced a number of problems:

1. Bookmarks do not sync between iPad 2 and iMac.

2. Bookmarks in iPad 2 cannot be added, deleted or modified. Also the Read Later folder does not work.

3. My mailboxes (inbox, sent etc) are all empty in iCloud. However, my mailboxes do sync between iPad 2 and iMac.

4. iPad does sync with iCloud and vice versa. However, input made in iCloud also sync with iMac but NOT vice versa. What's wrong if entries made in iMac (in iCal or in Address Book) do not go to iCloud (but they work other way around)?

Any idea?