> It's called proof of work.

> I did this for email. Get in touch if you want to try it.

How? Via email?

I'm not going to implement your proof-of-work scheme just to email you.

Nobody else is, either.

Thanks for writing the blog post. Insights like these and of such high quality are rare.

Can I ask what was the total cost of the migration?

If there was software that could do this database migration without downtime, how much would you/Guardian be willing to pay?