The poster at The Spam Chronicles is looking at how various programs and services handle (or don’t handle) spam.

First off, he compares Mail and Thunderbird by testing how well they process 109 spam emails released from his Gmail account.

The junk controls on both clients were reset at the start of the test.

He discovered that Mail flagged 42 of them as spam and missed 67 for a 39% success rate. Thunderbird faired better: it flagged all 109 as spam when its junk mail controls were run on the Inbox.

He them tried again with 61 spam emails from his Yahoo account and found that Mail.app “flagged 23 as spam while delivering 17 to the inbox for a 56% success rate” while Thunderbird again flagged them all when its filter was run on the Inbox.

He concludes:

Apple Mail starts with a more conservative approach in order to avoid falsely flagging e-mail as spam. In Apple Mail the spam filter is on my default. Thunderbird starts off with an aggressive filter but the spam filter is off by default and must be enabled.

Of course, this is not a neutral statistical sample sound for all eternity, nor is it fair to judge the clients on untrained filters, but the result is still interesting.

In another post he compares how a wider variety of web-based and Desktop email clients handled a week of spam, covering Yahoo!, .Mac’s webmail, Gmail, AOL, Apple Mail, Thunderbird and more.

There he finds out that on “the first day Apple Mail caught 10 and missed 10 junk mails. After that initial training it improved dramatically catching 6 and missing 1.”

For .Mac, he makes a perceptive observation: “.Mac mail does not have any web based spam filter, at least not visible to the user”. Nonetheless, “typically, only 1/2 the junk email appeared in my mailbox”.