The Weekend Effect
Fri, Apr 20, 2012 by Andrew Conway
We might imagine a spammer starting up their spam server and relaxing to enjoy their ill gotten gains on the beaches of Lagos or the Black Sea, but this is not the case. Just as Cloudmark’s spam filtering requires constant monitoring and enhancement by our dedicated operations and engineering staff, so a spammer needs to put in significant work to keep spewing sufficient volumes of toxic drivel to make a living. There’s an interesting static that demonstrates this – the total volume of spam goes down at weekends. World wide, we only see about 71% of the spam on weekends that we see on weekdays.
The weekend effect varies quite a bit depending on the country that the spam is sent from. The chart below shows the percentage of spam that turns up on each day of the week, broken down by country of origin. (The figures have been normalized so that each country adds up to 100 – in fact the majority of spam we see comes from servers or botnets in the US, and this would dwarf the other countries if plotted to scale.) Where the chart slopes down at the right that means there is less spam coming from that country at weekends.
As you can see, there is a strong weekend effect in Brazil and Italy, where the traffic goes down to less than 60% of the weekday average, but there is very little in China and Japan. Though all the top twenty spam source countries show some weekend effect it is least in Asia, with Japan, Vietnam, and China all having a weekend percentage of 90% or more of the weekday rate. Hong Kong, however, perhaps because of the British traditions there, weighed in with a respectable 69% weekend effect, 1% better than Great Britain itself, where the weekend was invented.
Here’s the full list
So why is the weekend effect so pronounced in Brazil and Italy? Is it because they are devout Catholic countries and the spammers are in church on Sunday praying for forgiveness? Or are they too hung over from partying on Friday and Saturday nights to send out any spam? Look for further reports on this if I can persuade Cloudmark management to finance field trips to Italy and Brazil.