On the forum I use most frequently, the most popular abbreviations are SWMBO (being about cars, most posters are men) TADTS (They all do that, Sir) BTDT (Been there, done that) sometimes with a GTTS added AFAIR (As far as I remember) and there are many more
Yes, there I do use these sets of initials when there. I do avoid them elsewhere and I certainly construct full, punctuated sentences when sending text messages.
(Oh, yes, whilst I am here, I always translate IMHO as in my honest opinion. Humility rarely comes into it!)
Nothing is foolproof to a sufficiently talented fool.