Thunderbird is the best email application available. It's an open source (free) project by Mozilla, the same folks that brought us Netscape so many eons ago, and more recently Firefox, Filezilla and Bugzilla to name a few. First let me point out that Thunderbird is not as susceptible to viruses as Microsoft products like Outlook and Outlook Express. Microsoft products tend to be targeted more by hackers, and the open source community has a lot more people protecting Thunderbird because they want to, not because it's their job at Microsoft.

What really makes Thunderbird so amazing is their intelligent junk filters. I use Thunderbird in conjunction with my ISP's spam service as well, a double-whammy that makes my email manageable. I manage several dozen websites and nearly every one of them has the webmaster@site.com address go to me, resulting in a tremendous amount of spam. Slow days may only bring about 50 spam messages. Busy days can bring hundreds of spam to my inbox. The most I ever had was a span of 3 days with about 13,000 messages each day. So you can see why I care about spam filters!

Using my ISP to mark them as spam as well as it can, I set up Thunderbird to automatically filter those messages straight out of my inbox and in to a junk folder. Any decent email application will do that for you. But my ISP misses a lot, and Thunderbird can be trained to recognize spam. Each message you mark as spam (a one-click process), Thunderbird learns from and improves its own filtering system. Marking it as spam automatically moves the message to your junk folder and helps Thunderbird filter out similar messages the next time it downloads more email. Thunderbird is smart and learns quickly, and at this point I only receive a few messages a day in my inbox that are truly spam, a much better solution than the dozens or even hundreds I saw in Outlook.