Black taxi drivers hate it -- and are willing to effectively shut down London to protest its existence.
But what actually is Uber? And why should you care?
Uber is essentially an app which connects drivers with passengers directly, instead of through a centralised booking service or just hailing a car in the street.
The app -- which is available on Android and iOS -- pitches itself as a safe and reliable way to get on-demand rides in most of the world's major cities.
Using GPS, it detects your location and connects you with the nearest driver. You can also request a specific type of car if you prefer - such as a luxury ride or a straightforward taxi. The app texts you when the driver arrives and you can check the identity of the driver against who actually shows up.
The app also gives you a price estimate, and is cashless -- you pay through the app, including tips. You can even split the fare between different riders.
It all sounds very convenient and simple, right? Well, yes. And also very similar to numerous other apps including Hailo, which works with Black Cabs rather than minicab services, and also established names like Addison Lee.
So it's no surprise that Black Cab drivers are upset. Among the obvious competition it represents to their business, they also say the app will lead to unlicensed drivers potentially putting riders at risk. They also say it is against established laws and regulations around hailing and metering cab rides, normally restricted to black cabs.
Still, if you want to try the app out, it's worth a look. Just wait until the strikes are over -- gridlock is not currently something that apps are able to sort out on their own.