Maybe this happens to you: you’re taking a break and looking at Twitter, and you see a tweet about a Call for Papers or an interesting history post. So you click on the link, and you get the screen above.
Are these public posts? No, they’re private ones, behind the wall of Facebook. Just because Facebook is widely used (yes, I have an account, too) doesn’t mean it’s an open source for information.
Sure, you could log in, if you don’t care about having your interests and clicks and data measured, which I don’t especially on FB. That’s the Mephistophelian bargain you make when you sign up for Facebook; as the old saying goes, if you’re not paying for the product on the internet, you ARE the product.
It’s one thing when the Association for Cat Necklace Distributors or some such thing wants to keep its organization behind the Facebook wall.
But when it’s supposedly public information? Or a supposedly open scholarly society? That’s irritating.
So if you see me retweeting, with an open link, the closed information and calls for papers that pass through my Twitter feed, that’s why.