Thanks! This begins to make more sense to me

> effects are handled by handlers

OK, and in the general case a handler allows its body to "perform" an action, and when the action is performed it has the ability to "respond" to it in (in some cases) a very flexible way, running it never, or multiple times, or in a modified environment, or possibly even passing it out of the scope of the handler entirely.

> function signatures describe the effects that are used

Would you say this is not possible in an untyped language then?

> effectful code is written in direct style, not monadic style

I don't understand the distinction here