Beginning 1 September, we will need to geoblock Mississippi IPs

Launch a small website and commit a felony in 7 states and 13 countries.

I wouldn't have known about the Mississippi bill unless I'd read this. How are we have to know?

I suppose this is what confused me then, as it seemed obvious that e.g. the Facebook reccomendation algorithm isn't speech, so if a social media site would be considered speech it would be due to the user content. Section 230 doesn't in any way supercede the constitution, but it does clarify which party is doing the speech and thus where the first ammendment would apply.

No, it immunizes certain parties from being held automatically liable (without separate proof that they knew of the content, as applies to mere distributors [0]), the "publisher or speaker" standard being the standard for such liability (known as publisher liability.)

It doesn't "clarify" (or have any bearing on) where the First Amendment would apply. (In fact, its only relevant when the First Amendment protection doesn't apply, since otherwise there would be no liability to address.)

[0] subsequent case law has also held that Section 230 has the effect of also insulating the parties it covers against distributor liability where that would otherwise apply, as well, but the language of the law was deliberately targeted at the basis for publisher liability.