Does SPAM Peak on Wednesday? 54
danlor asks: "After installing a pretty good spam filter here at work, we noticed an interesting weekly trend in overall spam intercepts. They peak on Wednesday and trough o n Sunday. It is an almost perfect bell curve. We have gone over this quite a few times here, but cannot come to consensus on why this would be. Could Spammers really be God fearing? Why would Spammers have a 'hump' day?" Has anyone else noticed this trend?
Graphs? (Score:3, Interesting)
Re:Graphs? (Score:4, Funny)
Posting graphics on Slashdot is a crazy thing to do, especially if you like being able to access your network!
Re:Graphs? (Score:5, Interesting)
http://www.pdrap.org/spam_statistics/graphs [pdrap.org] is my web page with the graphs. The total height of the bar is all the mail I've received. The red part is the spam.
The bottom graph is a chart of the accuracy of my bayesian spam filter. In just the three weeks that I've been tracking, the filter has gotten notably worse. I've noticed several spams that seem to be crafted specifically to get around bayesian filters.
Re:Graphs? (Score:1)
Maybe they send from work or school? (Score:3, Insightful)
NarratorDan
Re:Maybe they send from work or school? (Score:4, Interesting)
I bet if you graphed legitimate business email, it would show the exact same trends.
Spammers are people too, just barely.
Re:Maybe they send from work or school? (Score:1)
This took into account both the number of emails and the total size.
Re:Maybe they send from work or school? (Score:1)
Different Days (Score:3, Funny)
Of course getting inside the mind of a spammer would be something that would require danger pay.
Hmm... all these people really need to know about herbal vigara... and I'll be the one to sell it to them!!
People Effect (Score:3, Insightful)
blatent guess (Score:2)
Not for me (Score:5, Interesting)
Analyzing 11,560 spam emails that have come to my inbox over the last few years, here is the distribution over the days of the week: (What a pain it is to get a graph to reproduce correctly on slashdot!)
While it does show a "bell" with a peak on Wednesday and a dip on Sunday and Monday, it's certainly not significant. 20% less email on the lowest vs. the highest day isn't significant in my mind.
(Statistics generated with MailListStat [freshmeat.net] from freshmeat [freshmeat.net].
Re:Not for me (Score:2)
Re:Not for me (Score:2)
I just looked at the dates. Spammers lie on the "Date" header, so I looked at the dates in the "Received" lines. These 11,560 spams were received between 15 Jan 2003 and 15 Sep 2003 for a rough average of 40 spam messages a day.
Re:Not for me (Score:1)
If I sum up the values of Mon..Sun then I see that you get 620% of spam every week. That's of course quite a lot of spam.
Re:Not for me (Score:2)
One might argue that having the percentages be in relation to all spam received. But I think it's more useful to have it be on a daily basis, as that's what's being reported for that particular graph.
Re:Not for me (Score:2)
It's allotted loosely...
Seems to be valid english to me. Where are you going with this?
Re:Not for me (Score:1)
I wish all slashdot readers thought (and spelled) as you.
Re:Not for me (Score:2)
But it is significant. With about 1,651 emails per day of the week (11,560/7=1,651), the 1-sigma variation due to random chance is sqrt(1651)/1651 = 2.5%, assuming that the spams are independent of each other (Poisson statistics).
Your detection of a ~20% variation allows you to quite strongly rule out the nul
Re:Not for me (Score:1)
Waiting for inbox clean-up (Score:3, Interesting)
Many people I know, keep cleaning their inbox until tuesday indeed! So, Wednesday might be a safe day for spamming, as inboxes are emptier.
Because more people buy on a Thursday (Score:5, Interesting)
Re:Because more people buy on a Thursday (Score:1)
It's also possible that an advertiser jumped on a statistical anomaly, and feedback caused it to grow from there.
Re:Because more people buy on a Thursday (Score:1)
I think they don't necessarily know this, but many of them might use the same brand of bulk mailing software with this feature included.
Different for me. (Score:4, Funny)
Alex.
Re:Different for me. (Score:1)
Despite the "Funny" you got, you're probably right. It depends on which spammer crew (in my case, someone sending out emails in Russian with my domain forged in the header) is targeting you.
Two daily peaks? (Score:2)
I've kinda assumed this is because the spammers had day jobs and they spammed just before and after work, but it could also be because there is some reason spammers think we are more likely to read it at those hours.
One last though... isn't regular junk snail mail suppose to be sent to arrive on Friday's for some reason? Because it will sit on your kitchen table on the weekend?
Re:Two daily peaks? (Score:2)
I spoke with a spammer once (Score:5, Interesting)
But before I uncapped him, I was able to glean this much about their mailing habits: apparently, whether true or not, there is a prevailing idea in the spam community that Wednesday mid-morning is the best time to send spam.
There idea is that this maximizes the likelihood of it being read; they consider weekends not to be important because people are occupied with funner things than spam; they consider Monday and Tuesday to be "warmup" days into the week, when people may actually be doing work. Thursday and Friday they consider "slackoff" days in which people not only don't do work, but don't read email either. So that leaves Wednesday. And if you analyze your logs further, I bet you'll find that the peak within Wednesday is mid-morning, not the grogy, naptime after lunch hours. That's what I see with my filter, anyway.
Wrong approach (Score:2)
I believe it was Swordfish that had the line, "Have you ever tried typing with only one hand, Stanley? Pretty fucking hard typing with only one hand. If you want to keep both, you're going to do this."
Not that I can see (Score:5, Interesting)
I've been saving most of my spam for the past year or so. A quick scan of my spam folder shows the following breakdown, sorted by frequency:
Or, for the same data as a histogram (line length divided by 25):
Wednesdays are pretty much in the middle of the range (the mean is 824.9).
The bigger trend I've seen was a big spike back in May, but the rate has sloped off considerably since then, as this chart of month over month spam trends shows (line length is again divided by 25):
(The script that generated this is available on request.) A major cause for this change in trends may be a change in email address around then, but even before the switch I was seeing a dropoff in the number of spams I was receiving. If this pattern is more general than just my mailbox, I have no idea what's causing it.
Disclaimer: no general trends are implied, this is just "back of the envelope" analysis of the spam mail I personally receive. As noted above, if anyone wants the shell scripts that generate these charts, you're welcome to them -- they're just a few lines of Bourne code that scan over my mbox mailboxes. If you use something other than mbox mail storage, the script may or may not do you any good, but if you want it, ask. :-)
Re:Not that I can see (Score:2)
I only noted that because I've been asked for it before. The only reason I didn't paste it was because <irony>Slashdot makes it a pain in the ass to paste source code samples into comments </irony>. But you're right, it's trivial, and anyone could replicate it, I was just trying to be helpful...
Re:Not that I can see (Score:2)
I fitted a generalised linear model with weekday as explanatory variable and count as response. Here's the table of coefficients:
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) 6.72143 0.03471 193.642 <2e-16 ***
DayMon 0.06642 0.04829 1.375 0.1690
DaySat 0.01079 0.04896 0.220 0.8256
D
This seems to be a trend with legit email too (Score:3, Insightful)
This seems to be attributed to human nature. There is more correspondence going on Wednesday's because people just don't feel like doing as much work on Monday's and Friday's.
Yes, Virginia (Score:1, Offtopic)
(MMV) My mileage varried (Score:2)
At my site, the overall spam traffic is highest on the weekend but (and I have no clue why) the spam to real users peaks mid-week. The weekend trafic tends to be more baby-name-book-buckshot or (and would I ever love to get my hands on the clowns who think this is clever), "A@...", "B@..."
Spam Stats (Score:3, Interesting)
The spams to my Hotmail account spike on Friday evenings. Those are what I would call the "dregs of humanity" spams--the assorted barnyard animals, herbal enhancements, and general "Are you lonesome tonight" spams. They're also more likely to be inept, such as having a "TO" field that reads "C:\documents\addressfile.txt" or words to that effect.
Bagnallb at AOL is sort of my own personal spammer (although I share him with many other people on the greater Internet). He really, really wants to take over my domain, and he manifests this by increasingly frenetic efforts to find an obsolete version of FormMail. He's been trying without success for six weeks now, and his efforts always, always increase on Wednesdays.
So I'd say Wednesdays for the "business class" spam and Fridays for the really scummy stuff. Bagnallb is scummy, but he's a Wednesday sort of fellow.
They are just making a living. (Score:1)
online store stats (Score:1)
-visits peak on thurdsay and friday, they are lowest on sunday, awstats shows a nice regular curve.
-visits reach a peak about 10am, stay steady until about 9pm and then fall to lowest at 5am (Central Time)
Must be all those Microsoft security warnings... (Score:1)
I guess... (Score:2)
Wasn't Wednesday the trollday?
Your Wednesday is my Thursday, (Score:2)
Spammer workweek speculation (Score:3, Funny)
Monday - Check mail from the weekend. If no new lawsuits, laze through the day like everyone else.
Tuesday - Write some spam.
Wednesday - Send out spam.
Thursday - Await responses to spam.
Friday - Deposit ill-gotten gains in the bank, take off early for the weekend.
Re:Spammer workweek speculation (Score:1)
Sunday - Profit!!
Friday (Score:1)
Friday is spam day for me :)
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