It says something about Play Billing being used specifically to mitigate spam?

I understand using play payments initially but hopefully eventually there's a way to buy an account without going through google.

Add ability to pay for a signal login.

https://github.com/signalapp/Signal-Android/commit/7da3357b5...

Wouldn't that be related to data storage? Which they offer now? Or is that different?

Ah, I thought you meant using google play to do the payments to prevent spam unrelated to the cost. I know they are costing something.

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