Why do people use these square bracket now [ ]???

[GloomyWaters]

Just wondering - signed up for a free class and wondering if it's a new trend or am I just old fashioned I like the (( ))

Where are you seeing it? I haven’t noticed it.

In what context are they being used? They are normally used in quotes to indicate that the writer has changed a word or is adding an explanation. They're not interchangeable with standard parentheses.

I use them when referencing the year of legal cases but I've not seen them used in any other context (other than PP's point above)

Body shape ?