The advent of social media has seen a huge increase in the use of informal abbreviations, many recently added to the Cambridge Dictionary. We have always had abbreviations, of course. Well-known examples include IOU (for “I owe you”), used to give an informal written guarantee that you will pay back a sum of money, and x for a kiss, for example at the end of a letter.
The fact of using a small screen or keyboard to write means that we look for even more efficiency in how we write. Email communication first introduced a few, often semi-formal abbreviations, which are now often used out of context in speech in a playful or ironic way:
Fyi (= for your information), my weekends are for relaxing, not clearing up your mess!