This video is an excellent response to the constant chorus of sky-is-falling pedants out there worried about the “decline” of language. Texting and netspeak are actually fascinating new developments in written language, and we should all approach them with the kind of wonder and curiosity John McWhorter displays in this video.
Just in case you’re wondering, these kinds of phrases are by no means constrained to English. Japanese has some really excellent ones. For example, many people use （笑） or （ｗ） for many of the same pragmatic uses that LOL serves in English.