I found this fascinating quote today:
Just because Twitter is only 140 characters doesn’t mean that spelling, grammar, and clarity don’t matter. In fact, I’d argue they matter more because you’re communicating in such a compact package, and you’ve only a moment to make an impression (or break it). You can still make your Facebook updates coherent and well-composed. And by all means, if you’re blogging, you’d better be working on the fundamental skill that helps you articulate your thoughts.altitudebranding.com, The Secret Social Media Skill, Jan 2010
You should read the whole article.