Lemme try doing a TL;DR on the whole thing: NASA has been doing tests on a proposed form of propulsion that uses electro magnetism to generate momentum, which, if it works, could revolutionize space travel. Turns out some recent tests on this have yielded intriguing results that sugest that it actualy works. This has sparked much speculation on not only wether it actualy works or the test results were achieved due to a measuring error, but also the implications that this could have on the possibility of creating a working alcubierre drive, which is a theoretical form of travelling faster then the speed of light. The fact that its actualy a NASA agency doing said tests and that no one has been able to refute it yet has sparked a wave of optimistic anticipation and cautious skepticism around the whole thing.
Here's my take on the TL;DR:
Somebody said somewhere on some blog or otherwise that NASA is working on the EM drive, which was then picked up by a bazillion of hopeful nerdy sites and further disseminated among the geeksphere, its sheer volume and the magic phrase 'its NASA' lending it all wholly unwarranted credibility.
In all this, nobody seems to care that there are no actual official statements from the agency about the supposed world-shattering discovery, and everything is just hearsay and high hopes clouding people's judgement.
This '<insert credible actor> is working on <some variant of> EM drive that does <not physics here>' has been resurfacing every now and then for years.
It's just a craze and a failure of scepticism.