[xxpor]

The tweet promotion is an interesting point, but the letter to the editor is easier IMO. It's assumed that a human has read and selected the letter to the editor, which is why they'd have liability. For the promoted tweet, my first reaction would be to say, if a human affirmatively promoted it, they'd be liable. If it's pure algorithm, they wouldn't be if they took it down when served a notice.

[simonh]

That’s not the current situation under Section 230. You can even re-tweet or forward content posted by someone else and not be liable. Only the original author is liable. This is sensible baca use otherwise all sorts of innocuous relaying, trending and categorisation activity normal of forums and social media that affect the scope and visibility of posts could trigger liability.