For more sensitive information, such as those elements listed, it's more common sense that you'd encrypt that data and have a security policy, regardless of what state in which the people in your database reside.

The title of this article so broad it implies that if you simply had a contact database (with no sensitive information) containing Mass residents that you'd have to file a security policy and encrypt every piece of information.

There's no need to store any of those things in your database in order to allow card transactions.

Unless I misunderstood this, it affects you even if you only transfer the information to a 3rd party:

17.04: Every person that owns or licenses personal information about a resident of the Commonwealth and electronically stores or transmits such information...

Also many online shops allow you to save the info in case you want to reuse it in the future.

If you're not storing the information, presumably you don't need to encrypt the data that you're not storing. You do need to encrypt it while transferring it (i.e. use https instead of http), but if you don't do this already, shame on you!

Similarly, if you're storing credit card numbers in plaintext in a database, shame on you! That's worse than storing plain-text passwords.

I think the worst parts of this law are the "you have to file with the Massachusetts government" aspects. The technical stuff is basically common-sense data security that everyone should already be doing.

This is not my field, but don't you have to store card card numbers in order to do things like issue refunds?

Correct that, partial refunds.