Some points before people starts panicking:
The hack took place between March and May 20 of this year
Based on the time/period that it took place, I wonder why they didn't make a "public" announcement about that incident?

BTW, for those that would like to read the Coinbase letter without having to download the PDF file, you can refer to the following link instead
["Coinbase notification"]:
Hackers rob thousands of Coinbase customers using MFA flawDid news of the hack appeared just now or is it Reuters recycling old news to try to create FUD or something?
I remember reading a bunch of hack reports in the past few months but looks like this is the first time that they've made it somewhat public: