[AdrianEGraphene]

It's a phone number. It's probably been bought / sold a few times already. Unless you're on the level of Edward Snowden, I wouldn't worry about it. But maybe your sense of privacy is more valuable than the outcome you'd get from Claude. That's fine too.

[jiggawatts]

It's my phone number... linked to my Google identity... linked to every submitted user prompt... linked to my source code.

There's also been a spate of AI companies rushing to release products and having "oops" moments where they leaked customer chats or whatever.

They're not run like a FAANG, they don't have the same security pedigree, and they generally don't have any real guarantee of privacy.

So yes, my privacy is more valuable.

Conversely: Why is my non-privacy so valuable to Anthropic? Do they plan on selling my data? Maybe not now... but when funding gets a bit tight? Do they plan on selling my information to the likes of Cambridge Analytica? Not just superficial metadata, but also an AI-summarised history of my questions?

The best thing to do would be not to ask. But they are asking.

Why?

Why only them?

[goatsi]

It's an anti abuse method. A valid phone number will always have a cost for spammers/multi accounters to obtain in mass, but will have no cost for the desired user base (the assumption is that every worthwhile user already has a phone).

Captchas are trivially broken and you can get access to millions of residential IP addresses, but phone numbers (especially if you filter out VOIP providers) still have a cost.

[dist-epoch]

Just buy a $5 burner phone number. No need to use your real one.