From Chuck Fuller, via Baptist Press:
Ethically, Christians must think of Twitter no differently than other forms of speech. The biblical instructions concerning one’s words broadcast from the mouth apply also to words broadcast over social media. Try reading James 3:1-12, and replace each instance of the word “tongue” with “Tweet.” Really. Do it. See what I mean?
While Twitter etiquette is still at its dawn, I offer my simple seven rules for Tweeting with class:
1. Venting your petty frustrations only frustrates others.
2. Say what builds up
3. Tweet “such is life” moments
4. Resist the urge to make Twitter your personal sermon to the world.
5. If you wouldn’t share it in a room full of people at a casual event, then don’t post it on Twitter.
6. If, when in public, you don’t say, “Mr. So-and-So said I’m awesome and smart,” then, when on Twitter, also refrain.
7. Keep personal conversations personal.
A common thread runs through them. Twitter is a semi-public space. Tweeting is the equivalent of saying something very loudly in a large room full of people with whom you have varying degrees of relationship. Don’t Tweet what you wouldn’t say in that room. Rather, “give grace to those who hear” (Ephesians 4:29).
This is an abbreviated list and one where we modified the text of a couple bullets to make it more relevant. Read the entire list in context at Baptist Press – FIRST-PERSON: On Twitter? Biblical ethics apply there, too – News with a Christian Perspective.