Let's go back to 1999. Ok, maybe just last week. You receive a forward from your Aunt Nellie about the latest Internet hoax or how Neiman Marcus has some great cookie recipe that you must have. You think to yourself, yeah, I guess should be "in the know" about that, but I really don't care. If I did, I would have already read up on it or I'll do a search when I have the urge.
Or imagine a blog where all that is posted are messages like "You gotta see this -link-", or "Look what some funny guy said on the Internet...". Yeah, you might have even posted something like that once - I know I have.
Enter scene, re-Tweet. "Oh, you just have to know about this thing that I saw someone say in 5 words or less". You just won't be the same without this knowledge that I'm imparting to you. And, what gets more FAIL about RT is that you might have already been following the user that is re-tweeted. Yeah - so now, you get to read the information twice or more and not come to any better understanding.
So, when you think about re-tweeting that article, ask yourself: Why would I send this on? How is this not repeating information? How will this person's life be different because they read this? If you didn't write it, don't re-tweet it. Find some way to augment what was originally said, or get out of the game.
Don't re-tweet this.