Creative constraints are helpful, but for platforms like Twitter or Facebook not to have italics is constraint run amok. In fact, I think this lack of italics has substantially contributed to the toxic social media environment.
No italics leaves you only ONE OPTION.
The big problem with ALL CAPS is that it’s at least 7.2x more aggressive than italics, but without italics, it’s really your only option other than plain text Markdown styling. And most people don’t know plain text Markdown styling.
SO IT’S ALL CAPS ALL DAY.
Now all you fancy writerly people who think that italics, like exclamation points, are for losers, or overused, or whatever… look, most people aren’t fancy and writerly like you. We write more conversationally. Italics are helpful to us.
Italicize any word in “I didn’t say she stole my wallet” and the sentence takes on an entirely different meaning (and when all you have is ALL CAPS for emphasis, it’s impossible to emphasize the “I” in that sentence, just saying).
It already takes a lot of effort for most of us to get our point across in writing. When you make us shout every time we just want to emphasize a few words, you’re raising the temperature in the room.
Adding italics would bring down anger at least 4.8%.
Italics for world peace.