SpamSub.exe is a part of Spam Subtract by Intermute. More information can be found here.

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On a daily basis email Inboxes are filling up with unsolicited junk email. Analysts report, on average 50% of all email is spam. The result: frustrated users who spend half their time using email manually sorting and deleting junk email. SpamSubtract is InterMute?s spam blocking solution. SpamSubtract is an easy-to-use, program that keeps unwanted email out of your Inbox.