In this context, the question is whether something is political speech or something else. What is included and excluded from that category will get pretty interesting.
We saw the same thing with compelled union dues in the public sector. Were those for political speech or just routine union activity? SCOTUS said it couldn't tell the difference, so a public institution couldn't compel employees to pay dues.
I guess twitter thinks they can tell the difference, but I suspect there will be a lot of controversy.