Getting back to managing spam received. The best plug-in is SpamPal that acts as a received mail proxy server. And sits between your real email ID and your local mail client. Mail headers are scanned to see if messages originate from a list of known spammer IPs. As well as from country domians like .cn (China) and .kr (Korea) that are commonly misused by spammers.

You can also add plug-ins like the Bayseian filter that attempts pattern matching. And while this technology is constantly 'learning' with detection improving over time. It takes it at least a week to sort through messages received and classify them. You can also define black (blocked) and white (approved) address lists. Mail marked as spam has a tag phrase added to its subject line. This tag phrase (typically **SPAM**) is then used by your email client's rules engine to redirect such mail to the Deleted Item/Trash folder. Or to a Junk Mail folder.

SpamPal is free to download and use. There are also lots of free plug-ins available to extend its efficiency. For more on how the software works at detecting junk mail, visit its web site.