Signal is the world’s most widely used truly private messaging app, and our cryptographic technologies provide extra layers of privacy beyond the Signal app itself. Since launching in 2013, the Signal Protocol—our end-to-end encryption technology—has become the de facto standard for private commu...
“As of January 2022, the platform had approximately 40 million monthly active users.”[0]
In 2022 they had $30M expenses, so the cost is somewhat under $1/user/year.
They said the minimum donation is there to reduce the viability of scammers using it to check if a stolen credit card number is valid.
[0] https://en.wikipedia.org/wiki/Signal_Foundation
What extra protection does 4 dollars get you?
400 times the 1 cent protection
The point of scammers using a small value to test stolen numbers is they hope such small transactions go unnoticed for longer, allowing them a bigger time window to use and abuse the stolen card number.
That just doesn’t make a lot of sense. I would question something under a dollar way more then something under $10
That makes you the exception, and not the rule.
Its not about protection or even going unnoticed like the responders say. I’ve fixed unprotected payment systems on websites, the real problem is they use it to validate CC information as live. By raising the cost, you make other lower hanging fruit more appealing and keep scammers from using your service to test CC info.