ApexMail

Features: Filters or blocks unwanted email.
Available for: Windows/Mac OS X/Linux
Cost: $24.94/year

BlackIce Defender

Features: Manages cookies. Manages computer history/cache. Hides browsing information. Is an anonymous Internet Service Provider. Enhances the security of online transactions. Limits personal information given to online merchants. Enhances email privacy. Enhances instant messaging privacy. Erases certain files on my computer. Erases remnants of my computer work and makes them irretrievable. Encrypts files. Creates an encrypted disk drive or partition. Hides files and/or folders. Reports spam. Filters or blocks unwanted email. Provides multiple, tagged email addresses. Gives a challenge-response to incoming email. Firewall. AntiVirus.

Available for: Windows
Cost: $39.95

Bluebottle

Features: Gives a challenge-response to incoming email.
Available for: Windows/Mac OS X/Linux
Cost: Free

ChoiceMail One

Features: Gives a challenge-response to incoming email.
Available for: Windows/Mac OS X/Linux
Cost: $39.95

Clean My Mailbox

Features: Filters or blocks unwanted email.
Available for: Windows/Mac OS X/Linux
Cost: $10/month

CruelMail

Features: Gives a challenge-response to incoming email.
Available for: Windows/Mac OS X/Linux
Cost: Basic account free for the first year, $10 thereafter. Gold account is $10 the first year, $25 there

Despammed.com

Features: Filters or blocks unwanted email.
Available for: Windows/Mac OS X/Linux
Cost: Free

Email Systems

Features: Filters or blocks unwanted email.
Available for: Windows/Mac OS X/Linux
Cost: Free trial, then $5.95/month

Emailias

Features: Provides multiple, tagged email addresses.
Available for: Windows/Mac OS X/Linux
Cost: $4.95/month; $9.95/3 months; $19.95/12 months

Hushmail

Features: Enhances email privacy. Filters or blocks unwanted email. Gives a challenge-response to incoming email.
Available for: Windows/Mac OS X/Linux
Cost: Free; $29.95 for premium account

iHateSpam

Features: Filters or blocks unwanted email.
Available for: Windows
Cost: $19.95

Mail Moat

Features: Provides multiple, tagged email addresses.
Available for: Windows/Mac OS X/Linux
Cost: $5/month or $20/year

Mailbox Guard

Features: Filters or blocks unwanted email.
Available for: Windows
Cost: $29.50

Norton Internet Security

Features: Enhances email privacy. Enhances instant messaging privacy. Filters or blocks unwanted email. Firewall. AntiVirus.
Available for: Windows/Mac OS X
Cost: $69.95/one year of updates; $39.95 for upgrade

Platinum 2006 Internet Security

Features: Enhances the security of online transactions. Filters or blocks unwanted email. Firewall. AntiVirus. Detects/Blocks spyware.
Available for: Windows
Cost: From $24.99

S-mail

Features: Enhances email privacy. Filters or blocks unwanted email.
Available for: Windows/Mac OS X/Linux
Cost: Free; $5/month for premium account

Sneakemail

Features: Provides multiple, tagged email addresses.
Available for: Windows/Mac OS X/Linux
Cost: Free; $2/month for premium account

Spam Gourmet

Features: Provides multiple, tagged email addresses.
Available for: Windows/Mac OS X/Linux
Cost: Free

SpamAssassin

Features: Manages cookies. Manages computer history/cache. Erases certain files on my computer. Reports spam. Filters or blocks unwanted email.
Available for: Windows/Linux
Cost: free

SpamCatcher

Features: Filters or blocks unwanted email.
Available for: Windows
Cost: $29.95

SpamKiller

Features: Reports spam. Filters or blocks unwanted email.
Available for: Windows
Cost: $39.95

Sunbelt Anti-Spyware Bundle

Features: Filters or blocks unwanted email. Detects/Blocks spyware. Blocks Spyware Pop-ups and Unwanted Advertising.
Available for: Windows
Cost: $38.95

ZoneAlarm Pro

Features: Manages cookies. Manages computer history/cache. Filters or blocks unwanted email. Firewall.
Available for: Windows
Cost: $49.95