[happymellon]

I can pick up PAYG Sims for verifying for essentially nothing (I think the cheapest I've seen here is 10p).

A phone number proves, and stops nothing.

If you can't detect spam from either the message, the volume or from other users reporting, then you have bigger problems.

[MagicMoonlight]

But you can’t automate that trivially

[happymellon]

If I wanted to automate I would use a bulk VoIP service.

You are focussing on the wrong point, I only mentioned that because I could get on these services with a disposable number.

[pc86]

From a technical standpoint it's trivial to identify and block voip services.

Phone verification isn't designed to stop spam, it's designed to make it prohibitively expensive to scale spamming, and it seems pretty good at that. If you want to get around phone verification in a quick one-off fashion, yes it's going to be really easy. But there's no way to automate that one-off end run at scale without a lot of money and/or a lot of people. That's the whole point.

[derefr]

It's trivial to identify and block VoIP prefix allocations. That's different from identifying/blocking VoIP services, which — especially in the case of blackhat services — can operate entirely by buying and porting one-off numbers from residential cellular ISPs.

[tinus_hn]

So if you are so well versed in the matter, what’s keeping you from starting a chat service that doesn’t require phone numbers?

Apparently people are willing to invest a lot of money, that could be yours!

[justsomehnguy]

It just rises the upfront costs, but if the revenue exceeds these a thousand times...