Dean Anderson wrote: > On Fri, 13 Feb 2004, Ed Gerck wrote: > > > Shannon distinguished messages --or intended information-- from noise. > > The distinction beween noise and information is that information is what > > the sender wants to send or, alternatively, what the receiver wants to > > receive. If the channel is a covert channel, it is fair to assume that > > either the sender or the receiver (or both) do not intend it to exist > > (otherwise, it would not be a covert channel). Thus, a covert channel > > transmits information that can be considered for modeling purposes as a > > source of noise. Since the 10th theorem applies to any source of noise, > > it also applies here. > > You are confusing a covert channel with noise. They aren't the same. Of course they aren't -- how could a channel be equal to noise, anyway? What I said is that the *information* transferred by a covert channel, whatever that information might be, is NOT the message (the intended information). Thus, for modeling purposes in terms of Shannon's information theory, the choice is clear. The *information* transferred by a covert channel is noise (the only other possible option). > Antispammers have commonly used an analogy that equates spam with noise > and anti-spam efforts as trying to find a "noise filter". The analogy > sounds good, but is not accurate, which might suggest a reason why they > have failed to find a "filter". If you are proposing a different model, fine. There are always many models that can describe something. However, in the message model used by Shannon, there is a clear distinction between messages (or intended information) and noise (anything else) that also applies here. In the case of spam, my mailbox has messages (intended communications) and spam (noise). Also, note that noise does not have to disrupt communications! Noise is simply that which is not the message. BTW, I often find people who try to say that spam is not noise -- because it can be useful, as advertising. Surely, in terms of a communication process, you can consider whatever you want as the *intended message* (i.e., not noise). You can certainly say that spam is a message that the sender (the spammer) intended to send. However, from the receiver's viewpoint, spam is usually considered to be noise and IMO rightly so. > Spam isn't unwanted until after the fact: You read it, and then you don't > like it. I strongly disagree -- I don't read spam and I don't even try to read the unsubscribe information in it. I try the best I can to detect it and delete it as early as possible. If possible, even before it is queued in my mail box and causes me further problems (and costs). I believe that's also what the majority of email users would like to do -- or, do you really think we all have the time to read spam and decide after the fact that it is indeed spam? That's why the proposal for anti-spam burden does provide a mandatory pre-delivery burden that can be increased as much as the *recipient* wants. Users should not be burdened with reading and sorting out spam -- regardless how the senders want to classify it!