I think the real takeaway is "Social Login Buttons Aren't Worth It _For B2B_"
Very few people are going to sign up or log into a business account using a personal facebook or twitter account, and few businesses are going to have a lot of people with direct access to their facebook page and twitter feeds.
We've found that allowing social logins on our site (ecommerce) only causes confusion for our customers.
"We can't locate your order under that email address. No, not that username either, keep guessing..."
We have found it's best to either not force customers into account creation at all, or make it super easy (ie. a checkbox "yes" and password prompt on the checkout page only).
Imagine if linked in or something similarly businessish got into that space.
I have a hotmail account I use for all my professional MS related needs that has become my business social sign-on account. In general, there's room for innovation here. Google really screwed the pooch when they decided Plus Circles were an internal organizational tool instead of a public facade.
Very few people are going to sign up or log into a business account using a personal facebook or twitter account, and few businesses are going to have a lot of people with direct access to their facebook page and twitter feeds.