Note that this is the opposite of most questions. Which sites tend to be the worst for promoting poor practices?
Edit: I guess I wasn't clear enough, although one person made an answer into a comment that might otherwise have been promoted. I'm looking for places that SAY they teach you X programing knowledge, but instead teach you things that make programming difficult or otherwise tell you things you'll later need to unlearn. The more widely advertised such a tutorial site is, the more useful picking out it's poor potential might be here.
I suppose it's possible that there is no such site on the internet. But I doubt it. Hasn't anybody ever said to a newbie "Oh, don't go to X site, they don't know squat."?