First rule of thumb, never, ever, give away your private keys in any circumstances, or let anyone else know about your private key. Even if they don't steal your coins now, they have the ability to retain that private key and access your funds later.
These phishing scams are targeting crypto users, always check the url carefully when you click on something in your mailbox. Also, check if the sender's credentials are legit. Best thing to do is just don't click on anything from emails, although sometimes that's not possible. Have a bookmark or just remember the website URL.
Thanks for the PSA. I've seen both these cases (MEW and Coinbase) reflected elsewhere as well, I think. Not sure how many people fell for it, though.
Phishing attempts are not hard to avoid but the question is how they got your email? I believe that some exchanges have their databases leaked or even sold because these attacks seem to target crypto users only.
Yeah, I believe that cryptopia was one of the targets that had a database leak. But it's honestly all speculation where your email was obtained from, it could be some shady site that you signed up to. There are loads of possibilities honestly. But that's a reason to be careful when you sign up to random sites.