People coomunicate through chat and other message systems, as well as informal emails, so it does become natural to use abreviations- I have to check several email addresses from this site as well as my personal account, and the load of e-communication is growing for most people.
If you mean actual examples, useful one are things like brb (be right back), while ROTFLMAO (rolling on the floor laughing my ass off) has always struck me as rather silly.
l8rs
