The proliferation of abbreviations is an index of the hyperkineticism of present-day life and communication. This old man is having a hard time keeping up.
Category: Abbreviations
OTT
Internet abbreviation: over-the-top.
Abbreviations divide into acronyms, initialisms, and truncations. Or so say I.
See Acronyms, Initialisms, and Truncations and Acronyms, Initialisms and Truncations: Another Look
TL;DR
The hyperkineticism of present-day communication forces one to be pithy, which is good in many contexts. The downside you already know about.