All your friends are using Zoom, the video-chat app that is suddenly dominating competition from Google and Microsoft

The most clear evidence that Zoom is doing well is its position atop both the iPhone and Android top-downloaded apps charts.

It's so popular on mobile that it's 2nd only to TikTok as the world's most downloaded app across the last week. During that period, Zoom added "close to 20 million new mobile users," according to data provided by mobile data analytics firm Sensor Tower.

And many of those downloads were first time users: "Globally, first-time installs of Zoom's mobile app increased 213% last week compared to the preceding week of March 9, and 728% compared to the week of March 2," Sensor Tower's Head of Mobile Insights Randy Nelson told Business Insider.

"Zoom's mobile app was installed about 3.7 times more than Skype's and 8.6 times more than Google Hangouts," he said.

Whether you're talking to friends or your teacher or your boss, it never hurts to look your best.

To that end, Zoom has a built-in beautification filter, which is one of several relatively silly little details about the service that help it stand out.

Zoom's virtual backgrounds are another crucial detail: You can swap out whatever is behind you in the video for, say, the Milky Way galaxy, or the top of the Burj Khalifa, or the interview area from "The Office."

But more important than any of that stuff, according to the users I spoke with, is functionality.

"I prefer the [user experience] and find call quality consistently better," one user who operates a small business said. "You can record the meeting," another user pointed out.

An associate who works in video game development said, "You can stream much higher quality video via Zoom than Hangouts. Trying to view a video clip (or live gameplay) over Hangouts was impossible. Zoom is much higher quality than Hangouts by a long shot."

It's easy to see why this stuff — better call quality, the ability to record meetings, and being able to share high-quality video over that call — help to set Zoom apart from the competition.