Ignoring privacy / monopoly concerns, Facebook is also remarkably inconvenient for reading long-form writing.

• The main feed semi-randomly decides what it thinks you want to read and may decide not to show you something at all.
• You can set it up to notify you about new posts from a particular person, but that gets annoying with longer writing (since you can't easily tell it to remind you later).
• Saving to services like Pocket doesn't work right.
• There's no RSS feeds.

Twitter and Tumblr have similar problems. I thought Reddit did too, but they actually make their RSS feeds easy to find, although it's fairly annoying that they're not full-text (makes it much harder to read on a phone).