Jeremy Lizt, one of my colleagues at Rapleaf, recently pointed out that spam usually arrives at night or over the weekend. We believe that might be because bandwidth costs are lower then.
i tried to find some more information on when spam is more likely to arrive and i couldn’t find anything. if anyone has some stats like this, please email me. thanks!
I haven’t seen specific statistics on this, but lots of spam today is generated by zombie machines (i.e. computers with viruses that send emails without the user’s knowledge).
In these cases, it makes sense that activity is initiated when the user is not actively using the computer (late night hours) to leverage spare CPU cycles and keep the virus undetected. With infected cable/DSL customers, bandwidth availability (for last mile) is the driver rather than bandwidth costs.