When I log in to a social network, that should be it.
Let me repeat that: When I log in to a social network, that should be it. As in, that should be the last time I have to log in to anything, until I log out and log back in again at a later time. But apparently, some companies do not agree with this sentiment.
Here's an example:
Personally, I'm with the commenter. Perhaps others will disagree, but I firmly believe open, public social networks are no place for content trapped behind logins. I think there's an inherent assumption that content shared via social media is free and open. So when you entice people to content they can't ultimately access, well then, that's going to tick a lot of people off.
If the only content you have to share is behind a login, perhaps your community would be better served by a private social network they can join. Or perhaps you need to keep your outreach contained to an email listserv. OR, this may mean you need to invest in more resources to create original content for your social channels.
Bottom line: Don't ever share content behind a login over a public social media presence. Ever. But that's just my opinion. What's yours?