Acronyms have always been an integral part of computer culture, and they have since spawned a new language on the Internet. Commonly thought of as a series of letters that make up a 'word' there is a distinction between acronyms and shorthand.
Online enthusiasts are learning that shorthand are in fact called acronyms, but this is incorrect. The difference between acronyms and shorthand is that with acronyms, you pronounce the letters as a new word (for example, 'FUBAR' is pronounced 'foo-bar' and 'RADAR' is pronounced 'ray-dar'). In contrast, shorthand pronunciations are like an initialism (a set of initials) in which you say the letters one-by-one (for example, 'ESP' is an initialism for 'extra sensory perception' whereas 'esp. is an abbreviation for especially). The online practice is to refer to shorthand, initialisms, or abbreviations as acronyms.
The majority of the expressions you see above are not acronyms, but rather shorthand used while text messaging or IMing. There are several terms to describe different kinds of jargon including anacronym, backronym, weather acronyms, city acronyms, leetspeak and textonyms. BTW: If you ever see someone TYPING AN ENTIRE SENTENCE IN ALL CAPITAL LETTERS that means SHOUTING! It is not proper netiquette to TYPE IN ALL CAPS (even in email), in fact, it's annoying. People with limited eyesight may use all caps to see the words better, but otherwise, TURN THE CAPS LOCK OFF, unless you're using an acronym or shorthand.