What security concerns are there regarding website users inputting personal financial data without putting in personally identifying data?

I am a web developer, but I have only a rudimentary grasp of security, e.g., be careful to sanitize inputs, store as little user data as possible, encrypt passwords, keep up with security issues of libraries and packages, etc.
Today, I was… Continue reading What security concerns are there regarding website users inputting personal financial data without putting in personally identifying data?