I'm using Microsoft Outlook 2011 for Mac and I'm getting so much spam I'm not sure how to control it. In the past, I always applied "Block Sender" and "Mark as Junk" to any spam email messages I received. This doesn't seem to be enough nowadays.

Then I've started using Tools > Rules to create rules based on subject, but the same spammer keeps changing subject lines, so this isn't working. I've been tracking the IP addresses they also seem to be changing with each email.

Is there any key information I can use in the email to apply a rule to successfully place these spam emails in the junk folder?

I'm using a "Low" level of junk email protection. The next higher level, "high", says it may eliminate valid emails, so I prefer not to use this option.

There's maybe one or two spammers sending me emails, but the volume is very high now.

I'm getting a variation of the following facebook email spam:

Hi,
Here's some activity you have missed. No matter how far away you are 
from friends and   family, we can help you stay connected.
Other people have asked to be your friend. Accept this invitation to see your 
previous friend requests

Some variations on the subject line they've used include:

Account Info Change
Account Sender Mail
Pending ticket notification
Pending ticket status
Support Center
Support med center
Pending Notification
Reminder: Pending Notification

How do people address this? Can it be done within Outlook or is it better to get a third party commercial software to plug-in or otherwise manage it?

If so, why would the third party be better than Outlook's internal tools (e.g. what does it look for in the incoming email that Outlook doesn't look at)?