When I first started chatting, about 8 years ago, I came across the chat lingo. I pride myself on my short learning curve and I picked up the chatspeak very quickly. Within a short span of time I knew what ASL meant and what BRB stands for. (Age/Sex/Location and Be Right Back). There were so many others, some easy to guess and some I had to ask or look up on the net.
I could understand the reason for that. The bandwidth was limited, and the typing work more, so it made sense to say "i m good, how r u?". Somehow, over time that trend changed. Computers became even more closely integrated with our lifestyle and pounding on a keyboard became more common than picking up a pen. With that the trend changed, chatspeak began to be considered unwelcome and boring by more and more people. As a very addicted chatter and online gamer I have seen this trend develop. I have seen profiles where people specify that they don't want to talk to anyone who uses chatspeak.
I guess there are several reasons for that. One is the focus on time. Why are you saving time? If you are so short of time why are you wasting time on here? This is a pleasure based activity and not mandatory. On the other hand, if it's not for pleasure but an important communication then chatspeak is totally rude. Just as we observe table manners in deference to others, similarly, writing a well-phrased communiqué using full words shows that you care enough about the person to take time out to write properly.
I still come across people who use chatspeak in chat or emails. It turns me off immediately and sometimes infuriates me. It shows that the person is not in touch with the current trend and doesn't care about my feelings. Esp. after I have told them about it. Most of the time such people are newbies or out-of-touchers from the net, and sometimes just inconsiderate. It saves them 30 seconds by using chatspeak, they don't care if takes you longer to decipher it or makes the email look unprofessional and ugly.
Some of it, like LOL or BRB is kind of essential especially in chat where LOL is being used like 10 times every minute or you may need to say BRB quickly when the doorbell suddenly rings. I have some personal follies like saying 'cos' instead of 'because' which I try to avoid most of the time but let creep in, sometimes in personal emails or chat. Otherwise even in personal emails, I take care to write without using chatspeak and using proper punctuation. I think it helps me to write well and improves the flow.
Now I am debating the question of whether to boycott the people who insist on using chatspeak extensively in emails even after my telling them that it's not welcome!