Universal Dibbler Field Theory
Another excellent post from the WMG (Wild Mass Guessing) section of the Discworld TV Tropes page:
The question has been asked, why are there so many Dibbler clones scattered across the Disc?
We know, of course, that Time = Money. We also know that, on Discworld, concentrated Time distorts Space (see “Pyramids”). So it should be unsurprising that concentrated Money should have a similar effect on narrative causality.
The local narrative strain spontaneously generates Dibblers much as mice are created by stores of grain. (You know, because of quantum.)
The operation of a Dibbler acts as a Money sink to relieve this local stress. A Dibbler is remarkably efficient; local wealth shifts to debt very rapidly. This shift of receding Money to the Red is so pronounced that it has been termed “The Dibbler Effect.”
Ponder Stibbons, of the Unseen University’s High Energy Magic Lab, has speculated that the “Dibbler Shift” occurs at or near the speed of ₵, a velocity that has so far exceeded his ability to measure. (₵ being speed with which a dwarf picks up a gold coin dropped on a tavern floor.)
Once the local concentration of Money has been reduced to a local median, the stress is relieved, and the world returns to equilibrium (with CMOT Dibbler offering his comforting array of sausages, meat pies, and ‘what the hell is that? Geddit off me!’)