ZydoSEO - 9:55 pm on Sep 26, 2013 (gmt 0)
On the site for BusinessXYZ I would have no problem linking to that business' Twitter, Facebook, Pintrest, and/or Linked In pages in the header, and I would definitely allow those links to be followed. This is a great way to help that business' social pages fill up the SERPs (crowding out the competition) when someone performs a search for their brand.
What I would NOT do is allow sharing links (+1 buttons, Like buttons, Tweet buttons, Pin buttons, etc.) to 20 social platforms for each of the 10 blog post listed on a blog home page, a blog category page, a blog tag page, or a blog archive page like many plugins do. That's 200 outbound links on your home page. Instead, I would typically show the social sharing button links ONLY on my post pages.