Zoom

According to several experts, Zoom has major security vulnerabilities.
(https://protonmail.com/blog/zoom-privacy-issues/) Zoom allows your boss to track your attention during calls, shares the copious amounts of data it collects with third parties, and has already had a major security vulnerability. Zoom does not use end-to-end encryption, but only uses transport layer security (TLS) encryption. And online trolls have also taken advantage of default Zoom settings to “Zoombomb,” public conference calls and disrupt them.
Also (https://gbhackers.com/zoom-vulnerability/)

Zoom lacks of privacy, is a proprietary software like Skype or Slack, it means you cannot control the incoming and outcoming datas from your device, pc or mobile.

I do think that any companies in this world should only use free - open source software, libre software and a free operating system.
Unfortunately, only a few companies and only a few people are aware of it.
We must convince people around us to use open source software. (Firefox, Thunderbird, VLC, Wire, Linphone, Bleachbit...)

How many Edward Snowden should talk to tackle this issue seriously and take it seriously ???
This Zoom stuff only deserves 1 star, not more.

The most unsecure video/conference calling application you can ever use.

There is a lot privacy and security concerns about zoom:
https://en.wikipedia.org/wiki/Zoom_Video_Communications#Criticism

I don't understand why schools still want to use this. This has probably be the one of the most unsecure and not privacy friendly product you could ever used as a video conferencing app especially as a free user since Zoom does not provide end-to-end encryption to your calls anymore meaning Government Agencies has access to your calls , not just the government though but anyone especially hackers which can have easy access to exploit your session since it's not end-to-end encrypted anymore. There are much better alternatives out there.

Here are some sources if you're curious:
The Guardian
The Verge
The Intercept
USA Today
NYMag