To view the online status for a contact you have to obtain authorisation from the contact - there's a menu option to send a request for authorisation. People who have imported pre-existing contacts may have imported the "authorised" attribute and so it's already working for them, but contacts created "new" in the 770 will require authorisation before your 770 can determine the online status of each contact.

One "bug" I've found is that the 770 sometimes disconnects from the Jabber/Google network (possibly due to the auto-away/10-minute timeout function) and once this has happened it's not possible to reconnect to Jabber/Google until I disconnect and reconnect the WLAN.