Macworld’s "Five favorite Entourage tips" recommends installing SpamSieve: http://www.macworld.com/...
Mailsmith 2.2 under new ownership, now freeware, adds more SpamSieve-related features: http://bit.ly/KfZgy
Blog post with a bit more info about SpamSieve and Time Machine: http://tinyurl.com/m9t4ps
Having lots of messages in an Apple Mail mailbox (such as Spam) can really slow down Time Machine: http://tinyurl.com/msov66
SpamSieve 2.7.5: http://bit.ly/UHvZG