In order of ascending importance:
Rule One. Your profile pic should really have your face in it somewhere, preferably featured prominently.
This is not a big deal, and probably more of my friends break this rule than follow it. It's just a pet peeve of mine. I get a friend request, and I'm like, "Wait, is this the 'Joe' that I met at a party the other week, whose last name I don't know? Or is it just some random guy who spams friend requests in the hopes of getting his friend count up? Gee, I don't know, because your profile pic is a shot of your dog or your kid or something. And I haven't met your dog or your kid. Hell, I don't even know if you have a dog or a kid!"
For things like e-mail, blogging, chat, by all means, use whatever you want for your profile pic (I do). It's just that part of the point of Facebook is as a means of locating old friends, acquaintances, etc., and if you don't have your face in your profile pic, it makes it that much harder.
Rule two. Don't post anything too controversial to your wall. Save that shit for blogs, forums, etc.
I've already discussed this one, so I'll just add one thing: If you were at a Thanksgiving dinner with the in-laws, you wouldn't spout off about religion or politics (or politically-charged topics like abortion, alternative health claims, etc.), would you? I thought so. So why would you say it, not just in front of your in-laws, but in front of your in-laws and everyone else you've ever friggin' met? Maybe some of them think your opinyuhn are dum.
Rule three. For the love of God, don't directly criticize someone on their wall. This is actually why I had to unfriend a friend of mine, because she broke rule #2 and I felt I could no longer obey rule #3 as a result. Like, really, you are going to call someone out and tell them they are wrong and a crappy person in front of all of their friends and family and acquaintances? The dangers of an argument getting out of hand is bad enough online even when the communication is private or semi-private. Now you are going to criticize someone publicly? Are you stupid or something??
I would also add the Hehir Corrolary to Rule Three: Especially don't criticize someone on their wall while they are grieving. Double especially don't criticize them in regards to the manner in which they choose to grieve. On their wall.
Yes, this actually happened, and it set in motion a chain of events that has caused me to lose my primary creative outlet and only regular independent social activity. Goddamn you Mark...
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