There are lots of really bad tutorials on the web, mostly posted by people who have no idea what they are doing, but managed to get something to work for just long enough to create a misleading web page.
You should trust very few of the technical tutorials that you find in the wild, especially Instructables, who have no quality control whatsoever.
Vendors like Sparkfun, Adafruit and Pololu post tutorials that can usually be trusted.