The Many-Worlds Interpretation is seriously mischaracterised in the summary at the top of the article (presumably not written by Ball himself) when it says this:
"The idea that the universe splits into multiple realities with every measurement has become an increasingly popular proposed solution to the mysteries of quantum mechanics."
This is a misrepresentation of what the Many-Worlds Interpretation actually suggests, and it is contradicted in the article itself by Ball:
"In effect, this implies that the entire universe is described by a gigantic wave function that contains within it all possible realities. This “universal wave function,” as Everett called it in his thesis, begins as a combination, or superposition, of all possible states of its constituent particles. As it evolves, some of these superpositions break down, making certain realities distinct and isolated from one another. In this sense, worlds are not exactly “created” by measurements; they are just separated. This is why we shouldn’t, strictly speaking, talk of the “splitting” of worlds (even though Everett did), as though two have been produced from one. Rather, we should speak of the unraveling of two realities that were previously just possible futures of a single reality."
The error in the summary is a common misrepresentation, and it leaves many people (including me, when I first heard of the Everett Interpretation) with the mistaken impression that the interpretation proposes some mysterious new mechanism that causes the entire universe to 'split' every time a physical interaction or observation occurs. This is pretty much the opposite of what the interpretation actually suggests, since its purpose is to dispense with the significance of observation and 'wavefunction collapse' in the Copenhagen Interpretation.
The physicist Max Tegmark (an adherent of the Everett Interpretation, who made a film[1] about Everett with Everett's son; a sad story, as Everett was unable to make a career for himself in physics due to the unpopularity of his most famous idea) I think puts it best when he says this about the Many-Worlds Interpretation in his book, Our Mathematical Universe:
"The rumours I'd heard suggested that Everett proposed crazy-sounding stuff like parallel universes and that our Universe would split into parallel universes whenever you made an observation. Indeed, even today, many of my physics colleagues still think that this is what Everett assumed. Reading Everett's book taught me a lesson not only in physics but also in sociology: I learned the importance of going back and checking the source material for yourself rather than relying on secondhand information. It's not only in politics that people get misquoted, misinterpreted and misrepresented, and Everett's Ph.D. thesis is a great example of something that, to first approximation, every-one in physics has an opinion about and almost nobody has read.[2]"
"The notion that at certain magic instances, reality undergoes some sort of metaphysical split into two branches that subsequently never interact isn't only a misrepresentation of Everett's thesis, but also inconsistent with Everett's postulate that the wavefunction never collapses, since the subsequent developments could in principle make the branches interfere with each other."
[1] https://en.wikipedia.org/wiki/Parallel_Worlds,_Parallel_Live...
[2] https://www-tc.pbs.org/wgbh/nova/manyworlds/pdf/dissertation... (Everett's original thesis)