The problem of backscatter, part 1

As the creator, editor and sole content contributor to this blog, I like to write about topics that are relevant to myself at the present moment.  For example, if we are dealing with a breakout of image spam, I will write a few posts about why image spam is difficult to deal with.  If we are dealing phishing messages, I will talk about the economic models of phishers and how they attempt to trick people into revealing their financial information.

One of the hot issues we have in spam filtering is the problem of backscatter spam (this was the hottest issue for a while until two other issues displaced it and climbed to the top of the leaderboard).  I readily acknowledge that there are a lot of sources out there that do an excellent job of summarizing the problem of backscatter spam.  I am going to add my name to the list.

Over the next series of posts, I will address why backscatter is such a difficult problem.  What is it?  Who sends it?  Why does it occur?  How do we stop it?  Why can't we do a better job of filtering it?  What are some of the techniques used to stopping it?  Are there more creative solutions? 

These are the questions I will attempt to answer over the next few days.