Until a court case says that the act of receiving bytes from an HTTP server constitutes agreement to a contract that was never even presented to you, it's hard to see how you can possibly have agreed to a TOS. The user must be presented with a TOS and have the option to reject it in order to have agreed to it.

In Hines v. Overstock.com, the court found Overstock.com’s browsewrap unenforceable because the website failed to prominently display the link to the online agreement in a way that would put users on notice of the website’s terms and conditions.

And if you think it's all because "you have to scroll to see the hyperlink" and that Twitter's one is valid because there's always a "Terms and Services" hyperlink in small text on the screen at all times, I can tell you of Nguyen v. Barnes & Noble, in which the court held that Barnes & Noble’s browsewrap was unenforceable despite the fact that the hyperlink was prominently placed next to the buttons users must click in order to complete online purchases.

Van Tassell v. United Marketing Group also states:

> Because no affirmative action is required by the website user to agree to the terms of a contract other than his or her use of the website, the determination of the validity of a browsewrap contract depends on whether the user has actual or constructive knowledge of a website's terms and conditions.

In other words, w.r.t. the enforceability of Twitter's ToS on users that have never agreed to it explicitly, they have the burden of proof and have to give the court convincing proof that you knew about their ToS when you broke it.

This is all based on a rather obvious common law standard:

> An offeree, regardless of apparent manifestation of his consent, is not bound by inconspicuous contractual provisions of which he is unaware, contained in a document whose contractual nature is not obvious. - Specht v. Netscape

So yes, I have seen cases not enforcing this paradigm.

Sources:

Specht v. Netscape: https://scholar.google.com/scholar_case?case=958708515918483...

Hines v. Overstock.com: https://scholar.google.com/scholar_case?case=163224540731670...

Nguyen v. Barnes & Noble: https://scholar.google.com/scholar_case?case=110038111392175...

Van Tassell v. United Marketing Group: https://scholar.google.com/scholar_case?case=174994243217056...

Embedding should be fine because that's being "published" by Twitter who you have already given permission to publish (cf [1]) although I'd have thought (IANAL) that a screenshot would be a good example of "fair use for commentary" except when e.g. news services embed tweets, they're often not commenting on those tweets specifically, just giving a general flavour of sentiment.

It's a minefield, probably.

[1] https://www.buzzfeednews.com/article/jwherrman/want-to-publi...