This is a cool thing which we couldn't do back on twitter.
If you're posting about things which could be triggering or unwelcome or just quite scroll byable, tap the speech bubble with the exclamation point and it will give you a banner to type in - homophobia, violence, not safe for work, gory images, cat porn - make it easier for people to not have to see things they don't want to see.
I should have done this when I shared screen shots yesterday.