Every time you have a question in regards to building certain properties, ask yourself this question. Would a (select any brand) follower do it? If the brand's follower would, then why not?
Imagine a channel loving girl; she sees a new purse and she is in love with it. Do you think she would be sharing it more than once on her facebook account? Do you think she would be sharing it more than once in her other social accounts? Probably not, she will only share it once in each account; this does not mean that she won't be sharing more content from channel in her accounts, but she won't share the same content more than once (most likely).
All I'm saying is that SEO/IM comes down to rational thinking a lot of the times, so just use your head and try to think what would you do if you were a follower of the brand you are promoting.