How we should manage Audience Manager Database Address Books. If I have multiple brand site and each brand has multiple countries site. I want one contact can subscribe in each brand. So how could I manage contacts among these sites. Please give me an expert suggestion. It will be highly appreciable.
It's a little tricky to answer with absolute certainty here, since it depends on a lot of variables. In the end, it's up to you to decide what works for you -- perhaps with the input of some expert consultants that can help you consider all of the variables.
From what limited information you have given, it sounds like you only need a single static Address Book. You could then control the brands that they are a part of using Keywords and filter the Contacts in each brand by the relevant Keyword (if that's what you want), using Dynamic Address Books or Dynamic Distribution Lists.
Again, there's lots of options to consider before deciding on a final design. Should your users always have access to all of the Contacts? Or only the ones for their brand? Does a Contact (profile) need to be the same across all brands or does signing up for brand A and brand B involve two different accounts? etc.