This used to be pretty popular on YouTube but i have seen much of it in a few years. Wikipedia doesn't seem to categorize it as either a type of electronic music or a style of DJing.
There are a few music techniques here:
Looping is done by using a tape or two (or more) that plays back what was previously recorded. An example is here: Cam Neufeld - Beaufort Sea Boogie
Beat-hopping is a technique done by techno artists where several rhythms are played on turn-tables and they use mixing techniques (cross-fader, filter slider) to bounce between the records and loops they are playing in efforts to create new rhythms. An example is Ritchie Hawtin - Minus Orange. Here the main rhythm is taken from Yello - Oh Yeah.