And that is totally fine.
But for the other kind of people, the ones who want to write and be read, here's the catch--not just your stories will be read.
Your blogs will be read. Your tweets. Your status updates. Your forum responses. Your official bio on your website. Your YouTube comments. Your...et cetera.
Now, if you don't care about how you come across as an author or a public figure, you shouldn't pay any extra attention to how you conduct yourself online.Which, again, is your choice, and if you're capable of perfect grammar, spelling, and manners on the first try at 2 a.m. after a long, grueling writing session, take no pause as you update Twitter. In fact, I salute you.
For the rest of us...my advice: think twice about each update. Treat your words outside your stories with the same respect you do the ones inside. Show the world that you are the gosh-darn MASTER of words no matter WHAT social network site you're on. Don't mess with me--I tweet because I can make 140 characters COUNT! I can make you laugh with a one-line Facebook status because I have POWER over these words and I USE it! Bahahaha.*
Doing so will not only make words and others wishing to wield the same word-power (patience, grasshoppers) bow to your mastery, it will also make you come off as a very nice person. (Excellent public image, by the way.)
*Cackling not strictly necessary.