Stochastic Ideations

Link: http://doi2.acm.org/358453.358454

Back in March 1982, Peter Denning wrote (President's Letter, CACM 25, 3, pp 163-165) about "Electronic Junk". I stumbled across this article recently and was struck by both how much and how little has changed in the intervening 27 years, at least as regards electronic mail.

Follow up:

Professor Denning spoke of getting "5-10 pieces of regular junk mail, 15-25 regular letters, 5 pieces of campus mail, 5 reports or documents (not all technical), 5-10 incoming phone calls, 10-20 local electronic messages, and 10-20 external electronic messages." The ratios have changed for many of us: I get relatively little physical mail, far fewer phone calls, and far, far more email -- several thousand a day, before filtering, of which perhaps 50-150 per day actually get through to me. Probably 2/3 of those are newsletters or mailing lists that I read-and-delete (or just delete!) fairly quickly, leaving me with about 20-50 messages per day that require significant time and attention. Even if that only amounts to five minutes per message, I'm still spending 1.5-4 hours per day processing email. And of course, some of those messages represent multi-hour projects, but I think of those as being somehow external to the regular email stream just to maintain my sanity.

Professor Denning asserted the necessity of automatic filtering even before the advent of spam, as well as unfiltered "urgent, certified, and personal" mailboxes. He didn't predict dictionary attacks, believing that having "unlisted" mailboxes would be enough; we now know that essentially all mailboxes have to be filtered. He did discuss "threshold reception" (essentially a "bid for attention" scheme) that is a form of "electronic postage". He did not predict "proof of work" (e.g., hash cash) schemes, but it's interesting that he recognized the fundamental economic problem with email (cheaper to send than to receive) so early.

Today of course we filter essentially all email. We don't have "bid for attention" but we probably should. Many of us do use multiple mailboxes (or at least multiple addresses); I use a new address each time I sign up at a web site so that I can turn the address off if it starts getting spam (which also turns out to make it easier to recognize legitimate mail!). Sender authentication such as DKIM will move ideas such as "certified" mail at least into the realm of possibility, although more work is of course needed.

He didn't get everything right. He proposes "importance numbers", essentially a way for the sender to assert urgency, without realizing that malicious senders would lie. He talked about individuals having multiple mailboxes without predicting the problem of managing more than one or two. He mentions "restricted access" mailboxes without mentioning the necessity for authentication; in fact, he seems to have failed to anticipate bad actors at all (spammers, phishers, etc.) -- although he did acknowledge junk mail. I think he probably thought of junk email, but not in the quantities that we see today. Interestingly, he talked about certifying message quality, but he didn't mention sender quality (what we would today call accreditation and reputation).

Despite these gaps, he understood the fundamental problem of managing information overload and that email was going to make things worse in the short run. There are some interesting techniques for that, but that's another topic.

For a contemporary reaction to his topic, see the June 1982 ACM Forum (CACM 25, 6, pp 398-400).