Although Facebook connect seems like a nice thing, I really dislike how it means that posting diffbot items means it goes directly to your wall instead of sent as a message. As a result, I won't be sharing content through diffbot until it gives me this option.
i think we assumed if you wanted to share with one person, you would use email, but maybe you don't have their email address on hand, so facebook is an easier way to share items.
i can look into it, it might be simple for me to add. i'll let you know.