I'm tech savvy. Can you explain how backing up your contacts would help in this situation?

It is my understanding that once contacts are deleted from the server as a side effect of deleting them from the phone, you cannot restore those contacts without getting personal confirmation from each person in the list, for each IM service - something that could take months or years, for those contacts who aren't frequently online.

Worse, with services which don't give every user unique names, it's impossible to restore from client-side data alone.

Even if you don't do anything wrong, how are you supposed to remove individual IM/Skype contacts from the phone that you want to remain connected with via other clients? According to this thread, apparently Maemo 5 does support selective client-side IM contacts, and there is a way to remove client-side contacts but it is stupidly convoluted: Remove your IM/Skype account entirely from the phone, and then reinstate it, adding back all the contacts you don't want to remove. That sounds like daft UI to me.