Thank you for answering, and I think you have a reason.
But there is this thing called “link juice” and I don’t think I want to waste it for Twitter profile, or FeedBurner page. It’s just a profile I don’t care about. I would rather focus on the site PR. Btw, as a minor detail, links from FeedBurner to my site are nofollowed, the same for Fb.
I already have a Fb LikeBox iframe which maybe is followed by Google Bot. The small social Fb icon is displayed in menus only on phones and smalltablets, and would be the second. Does this imply more “link juice” that is lost ?
I don’t know much about it, but maybe it would be useful an easy option, so admins can choose what they need for every specific link.