Let’s have a look at one of my favorite topics today: E-Mail Spamfilters. They are a quite helpful tool for keeping the inbox clean as long as you don’t fully trust their work. I know this sounds paradox, but what happens if they eat a message you wanted to keep? What if they don’t kill a spam mail for you?

E-Mail Spamfilters are made to check your E-Mails for unwanted messages and remove those. Most E-Mail clients have them integrated as in Microsoft Outlook or Mozilla Thunderbird – even most Webmailers (GMX, Hotmail, Yahoo,…) offer that functionality.

But nevertheless a spamfilter is always some work as it isn’t perfect and needs training. Sounds weird, but that’s it.

Spamfilters are trying to find specific patterns in our E-Mails. The first filters were looking for certain words in messages. If they found a match, the message was simply discarded. Modern Spamfilters are using a more complex ruleset, rating every message because of various things found. According to that rating the filter gets some kind of score for the mail which is used to decide if the message is good or bad. If the Spamfilter accidentally killed a good message or didn’t kill spam, you can mark a message as invalid flagged and train it that way. This will really improve the detection rate!

I don’t want to show Spamfilters as the only way to kill spam in your inbox – but it’s one method of many to be used. But that’s topics for future postings.