Isn't remembering your QQ number similar to remembering your phone number? I think the author is being overly dramatic as to how hard it is to remember it.
But that would be a really short article, I guess...
(1) Numbers in Chinese match well with the tonality of the language making it easier to remember (compare: "singing" numbers in any language works better to remember them).
(2) Chinese students are trained from a young age to memorize.
That's it basically. No "obsession". No hidden stuff. I also find articles like this pretty degrading.
That doesn't mean I'm not jealous of my Chinese half of the family to be able to remember numbers so easily whereas I can barely remember my PIN code :).
Now I have exactly one, my own, memorized. I suspect this is an effect of the particular way in which Westerners have come to relate to phone numbers and similar numbers just as the emphasis on numbers is an effect of the way Chinese came to relate to phones and computers.