I am familiar with Raspberry Pi, and I've read a lot of MagPis, which is the officail magazine of Raspberry Pi.
So I wonder if there is any official magazine from Arduino or something like that?
The Arduino blog is the closest you'll get to official articles. But unofficial sources would only be a google search away (not a mag though, just random articles I'd assume).
Some other blogs like Adafruit and SparkFun are deep related to Arduino world. These are pretty good sources to reference and update things.
I suspect that the problem is that "Arduino" is too general and too primitive.
You've got your Electronics hobbyist magazines that are likely to have a lot of Arduino articles.
You've got your Robotics hobbyist magazines that are likely to have a lot of Arduino articles.
You've got your home automation magazines that are likely to have a lot of Arduino articles.
etc...