Do you mean following and unfollowing in some sort of rapid succession?

With just follow/unfollowing, you can't truly encode Morse code. You would have to override a metadata field or agree on an external clock source to overcome the idempotent follow/unfollow action and encode language into the state machine.

Were you blocked?

More seriously, the events end up in a list, so a recipient would more likely "decode" them by comparing timestamps instead of "live" watching the actual sequence.

But I suppose if you timed your follows/unfollows really carefully, you could get certain patterns in the timestamps to appear which could be used to distinguish "long" and "short" pulses.

You only have 1 variable in your control, the time in-between follows. (I say this because there is no notification for "unfollowing" someone)

You need to represent 2 variables : the dot/dash to represent symbols, and the dit, the time in-between symbols.

If you want to do this you need some sort of 2nd action, a comment or a twitter like, that way we could represent the dot/dash with either action, and then space them out to time the silence.

Let's say you could follow and unfollow once a second and they knew it. Then you could replicate the dots and dashes by the length of time you toggled the status plus the gaps where you weren't toggling at all.

Eg in the first ten seconds 10 toggles, in the next 10 seconds a 5 second gap then 5 toggles. That would be dash, quiet, dot.

No, because the notification timing is not reliable. It can vary a lot depending on the load on that microservice at any given time. Also, how would you handle dits, dahs, and gaps?