There may not be the actual need for these little tricks anymore. For getting multiple copies it is nowadays more important to locate the print-dialog.
From Popular Mechanics, November 1936.
Such tricks and tips would I guess be common knowledge back when typewriters were in common use. Exchanged and passed on between users, both home and office. (I do think I remember being demonstrated this trick of loading a stack as a kid - 'ages ago'. But memory is an unreliable thing...)
When using a typewriter today there is usually no throng of fellow-users around you to help and assist with such little tricks. This is where the 'wired' world fills the gap and really helps out! From the basic (but potentially really confusing) "where's my 1 ?" to "best to not hit the full-stop (.) too hard".
With the digital world, the cost of communication and the impact of distance on communication has basically approached zero. Like Clay Shirky observed in this Wired article, this now makes niche-interests possible, even mini-niche interests like typewriters in the 21st century.
I think it could be argued that the mechanisms of the digital world are fueling this interest, enabling for this interest; "Meganiches can address any interest, even one that users themselves wouldn't have thought of until they stumbled across a captivating Web page."
Nice, this digital world :)