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Twitter said that's why they got rid of the SMS 2FA. They said it was costing millions to have that enabled for them. https://www.cnn.com/2023/02/18/business/t

Twitter said that's why they got rid of the SMS 2FA. They said it was costing millions to have that enabled for them. https://www.cnn.com/2023/02/18/business/twitter-blue-two-factor-authentication/index.html#:~:text=Disabling%20text%20message%202FA%20won,year%20%E2%80%9Con%20scam%20SMS.%E2%80%9D https://www.cnn.com/2023/02/18/business/twitter-blue-two-fac...

chimeracoder 3y ago
> Twitter said that's why they got rid of the SMS 2FA. They said it was costing millions to have that enabled for them. Previous Twitter employees have said that this is incorrect. Because Twitter began as an SMS-only (and then SMS-first) application (remember 40404?), they very early on established direct-connection infrastructure for sending SMS, meaning that they have a marginal cost of literally $0.00/message in most markets. Twitter still has to maintain that infrastructure, because they didn't get rid of SMS 2FA - they just restricted it to Twitter Blue users, so the overhead is still the same. Almost nobody else who delivers SMS today has that infrastructure, because it doesn't make sense for most services to build. The only place where Twitter was paying significant amounts for SMS was due to SMS pump schemes, which is a consequence of Twitter gutting its anti-spam detection, resulting in them paying for SMS pumping which was previously blocked.
- hn_throwaway_99 3y ago
  > they very early on established direct-connection infrastructure for sending SMS, meaning that they have a marginal cost of literally $0.00/message in most markets. I am very, very interested to understand how that works, because without more detail or sources I'm calling bullshit. I definitely understand how Twitter could have greatly reduced their per-message fee with telecom providers, but at the end of the day Twitter is not a telecom and is still at the mercy of whoever is that "last mile" for actually delivering the SMS to your phone, so I don't understand how they have no marginal cost here. Happy to be proven wrong.
  - dghlsakjg 3y ago
    Not who you are responding to, but my guess is that it was all fixed costs. They spend $20mm (or whatever) to maintain access, and maintain infrastructure and they get to send as many SMS messages as they want. So sending 1 costs the same as sending a 10 million. It isn't that they are free to send, its that they are charged for access to the system, but aren't charged per message.
    - lxgr 3y ago
      > spend $20mm (or whatever) to maintain access, and maintain infrastructure and they get to send as many SMS messages as they want. This is not how SMS pricing works in many, if not, most countries.
      - dghlsakjg 3y ago
        Is that true at scale? If I tell the telecoms that I want to send a billion messages per year it seems like they might be willing to take a lump sum instead of setting up the systems to bill based on usage. I have no experience directly with foreign telecoms, so I was simply explaining how something with no marginal cost could still be a very expensive system.
        dikei 3y ago
        > Is that true at scale? If I tell the telecoms that I want to send a billion messages per year it seems like they might be willing to take a lump sum instead of setting up the systems to bill based on usage. In most of the world, SMS is billed per-message, so it's basically no extra effort on the Telecoms side at all. In fact, Telecoms' online charging systems are fast enough to calculate users' data usage by seconds in real time, so they don't even blink at counting SMS.
      - nerdbert 3y ago
        I don't know of countries that mandate a minimum price. If you are doing high volume you are free to work directly with carriers. If you are drawing as much billable traffic as you are sending, then that could even be a wash.

chimeracoder 3y ago

> Twitter said that's why they got rid of the SMS 2FA. They said it was costing millions to have that enabled for them. Previous Twitter employees have said that this is incorrect. Because Twitter began as an SMS-only (and then SMS-first) application (remember 40404?), they very early on established direct-connection infrastructure for sending SMS, meaning that they have a marginal cost of literally $0.00/message in most markets. Twitter still has to maintain that infrastructure, because they didn't get rid of SMS 2FA - they just restricted it to Twitter Blue users, so the overhead is still the same. Almost nobody else who delivers SMS today has that infrastructure, because it doesn't make sense for most services to build. The only place where Twitter was paying significant amounts for SMS was due to SMS pump schemes, which is a consequence of Twitter gutting its anti-spam detection, resulting in them paying for SMS pumping which was previously blocked.

hn_throwaway_99 3y ago
> they very early on established direct-connection infrastructure for sending SMS, meaning that they have a marginal cost of literally $0.00/message in most markets. I am very, very interested to understand how that works, because without more detail or sources I'm calling bullshit. I definitely understand how Twitter could have greatly reduced their per-message fee with telecom providers, but at the end of the day Twitter is not a telecom and is still at the mercy of whoever is that "last mile" for actually delivering the SMS to your phone, so I don't understand how they have no marginal cost here. Happy to be proven wrong.
- dghlsakjg 3y ago
  Not who you are responding to, but my guess is that it was all fixed costs. They spend $20mm (or whatever) to maintain access, and maintain infrastructure and they get to send as many SMS messages as they want. So sending 1 costs the same as sending a 10 million. It isn't that they are free to send, its that they are charged for access to the system, but aren't charged per message.
  - lxgr 3y ago
    > spend $20mm (or whatever) to maintain access, and maintain infrastructure and they get to send as many SMS messages as they want. This is not how SMS pricing works in many, if not, most countries.
    - dghlsakjg 3y ago
      Is that true at scale? If I tell the telecoms that I want to send a billion messages per year it seems like they might be willing to take a lump sum instead of setting up the systems to bill based on usage. I have no experience directly with foreign telecoms, so I was simply explaining how something with no marginal cost could still be a very expensive system.
      - dikei 3y ago
        > Is that true at scale? If I tell the telecoms that I want to send a billion messages per year it seems like they might be willing to take a lump sum instead of setting up the systems to bill based on usage. In most of the world, SMS is billed per-message, so it's basically no extra effort on the Telecoms side at all. In fact, Telecoms' online charging systems are fast enough to calculate users' data usage by seconds in real time, so they don't even blink at counting SMS.
    - nerdbert 3y ago
      I don't know of countries that mandate a minimum price. If you are doing high volume you are free to work directly with carriers. If you are drawing as much billable traffic as you are sending, then that could even be a wash.