THAT is a very interesting press release (and itself raises the slightly circular question: are SEC press releases considered a valid instrument for releasing legal guidance on how to comply with SEC regulations?).
But: If the SEC regard Twitter as, to all intents and purposes, a neutral 'wire service', then that means the SEC allows Twitter users to assume - regardless of what Twitter's own ToS say - that Twitter distributes information fairly and impartially.
Weirdly, it's not clear that the SEC has any way to regulate Twitter to ensure that they actually meet that assumption. If they were to discover, for example, that Twitter DID route interesting tweets to their in-house investment management team before publication, it's not obvious that the SEC could do much other than issue a press release saying 'sorry, looks like our advice about this was wrong, Twitter turns out NOT to be an impartial information distribution channel, please stop assuming it is.'
I wonder to what extent the existence of that SEC guidance affects how Twitter and Facebook behave? Do they consider, when deciding to implement features that modify the flow of postings from publisher to receiver, whether they are creating a mechanism which contravenes the SEC's understanding that they implement a 'fair disclosure' mechanism? Should they? Should there be regulatory compliance reasons that oblige them to?
And, per the SEC's guidance, this also applies to "social media outlets like Facebook and Twitter", whatever that means. Baidu, maybe? Is TikTok a legitimate channel to release material information? Do TikTok's engineers know that?
https://www.sec.gov/news/press-release/2013-2013-51htm