What are the remaining 3 threats to email security?

According to the Email Admin the amount of spam sent is getting less. Personally, I haven't noticed this, but I only get a few each day. However, there are some threats to email security remaining.

1. Malware being spread via email

Malware hasn't been a problem on Mac ever except for some tries like Mac Defender. Security experts have been warning for a few years now that this is expected to change. So far this hasn't happened.

2. Information leaks

Most likely, you will find that information is leaked by accident. An employee includes something in an email message that is considered sensitive. That email, once it leaves the protection of your company, can now be forwarded on or even intercepted in transit. The contents can then be easily exposed revealing trade secrets, private information or even embarrassing content.

Leaks will remain a problem forever because it's in human nature to be hasty. Don't you love the checks "Do you really want to send a mail to the evil outside address xxx?" that makes sending mails such a pleasure in corporate environments. Do these checks really work?

3. Go phish

Phishing is a threat that has been on the radar of most IT administrators for some time. And with recent data breaches ... millions of corporate email addresses have been compromised and are ready to be used in phishing attacks.

Once upon a time phishing mails were easily recognized by their awful english. But it seems that most spammers had their english improved or the writing of these mails was outsourced to english native speakers. Even I had to check for some mails the header information to see if a mail was spam or not.

And of course, it may be very possible that the recent trend of less spam gets reversed soon.