I communicate with a lot of people every day. Most of that communication is done in written form, whether it be text messages, emails, facebook messages or comments, tweets, whatever.
I spend most of my day reading - either these messages, or blog posts, profiles, or (if I'm actually working while I'm at work) contracts, letters, etc.
I consider myself a tech-enthusiast. I like technology, maybe more than some people in my age-bracket. Certainly more than some of the people with whom I'm communicating, since many of them are more old-school (read: older).
Many of them would still prefer a phone call or sit-down meeting. They have only entered the world of text out of fear they might be left behind. I, on the other hand, text, tweet, post, link, blog, and pin with the best of 'em.
What I don't do is talk in shorthand. I don't lol, idk, brb, or spell the word "right" as "rite." If I use you're instead of your, it's an honest mistake, and not because I don't know better.
Nothing chips away at a person's credibility with me faster than when he speaks in shorthand, uses lol to punctuate sentences, or doesn't know that an apostrophe makes a word possessive (except when it doesn't).
Sure, I get that technology makes a lot of this more acceptable. Save a character, or a keystroke! It shows you're on-trend. It suggests you can keep up with the conversation, no matter how quickly it's evolving or how "old-school" you might be.
But to me, that's a double-edged sword. In this techie culture, most first impressions are made through words read on a screen. Isn't it better for that impression to be that you care about your image, and how you present yourself? Don't you want people to know you're smart enough to know better, and care enough to take the time?
The way we present our message has become the new perfect outfit. It shows our style, our form, our image, and how we would represent our friends, family, and coworkers.
Lol is the text equivalent to wearing pajama bottoms when you go to the store. Just because other people do it doesn't make it OK.