Wandering Thoughts archives

Old and new addresses and spam

In response to an aside wondering how fast spam fell off for disused email addresses, Henry Spencer wrote me to mention that his older address (disused now for many years) gets a lot more spam than his current address. I've been thinking about this since then and I've realized that I implicitly divide disused addresses into at least two different categories. Let us call these the old active addresses and everything else.

Put simply, the old active addresses were actively and generally widely used on the Internet in what is roughly the pre-spam era. Henry Spencer's old address is definitely one example of this, since Henry spent years being active (and famous) on Usenet. Old active addresses were visible to spammers in the era where spammers began accumulating address lists and as a result they made it on to a huge number of such lists. These lists seem to still circulate and recombine today, even though an increasing amount of the addresses are no longer valid; effectively they have an exceptionally and I suspect atypically long half-life.

(One of my old addresses seems to be like this, in fact, although not the address that prompted my earlier entry.)

Other addresses either weren't visible enough to make it on to those early spammer address lists or postdate them in general. These addresses are not so universal in spammer usage and so get hit less and, I assume, also fall out of usage faster and to a larger degree. These are the addresses where it's interesting to ask about the half life of spam. Of course what I think of as a general category here is probably some number of different ones that I don't really see because I don't have enough exposure to information about how spammers harvest and pass around addresses today.

(My impression is that one reason old active addresses are so heavily spammed is that these old addresses have become pervasively and basically freely available to spammers via many paths. I assume that newer addresses are harder and more costly for spammers to get, so they are less pervasive. This is probably an incorrect assumption.)

The real thing this has made me realize that I don't really know much about how modern spammers operate. Is there a modern equivalent of the old 'million addresses' CDs that spammers apparently used to sell and pass around a decade ago, for example? I have no idea.

(I'm not likely to find out, either, since doing so would take a bunch of work even to find reliable sources of information and I just don't care enough any more. My spam problems have been basically solved by us outsourcing the work to commercial software.)

Disused addresses and the impact of spam

Here's something that I've slowly realized, at least about myself: the annoyance and impact of a given volume of spam is disproportionately large on otherwise idle and disused email addresses. The less real volume the email address gets, the worse spam feels regardless of volume. I have some old email addresses that get perhaps one real email every six months and perhaps a spam email every week or two, and I find it teeth-grinding. Meanwhile I'd only find that (low) volume of spam irritating on my main address (which probably sees over a hundred email messages a day).

(In retrospect this is part of why I said postmaster addresses are dead.)

I've previously written about why I feel noisy addresses are dead and while I still agree with the low level mechanics of that, it's not what affects me here (one email message a week can't exactly be called 'noisy'). What I think it is is the ratio of spam to ham. On a relatively disused email address the amount of ham declines much faster than the spam rate while the reverse is true for most actively used email addresses. My disused accounts thus wind up with huge spam to ham ratios; almost everything they get is spam (but not quite everything, otherwise I could just set them to refuse all email).

Which leads me around to the (now obvious) conclusion that for me the annoyance of spam can come either from its volume (having to deal with spam very often irritates me) or from the ratio. If almost every time I see I have email somewhere my reaction is 'oh great, more spam', I'm not in a good place.

(I'm actually somewhat curious what the spam half-life of a disused email address is. I assume that spam volume drops off somewhat, for various reasons, but I have no idea how fast it drops.)