It's common for people to think that spammers have unlimited resources at their disposal for sending spam. In truth, spammers pay a variety of undergorund service providers to send email on their behalf, and these underground services charge spammers a fee.
Spam senders typically are paid on a performance basis, i.e. when the message is delivered. But there is a limit. The senders know they have a limited time to burn up each campaign and server. If they wait, they will have their IP's and their content detected and blocked. So, while they can keep sending more spam, they need to be fast about it and cannot wait for slow servers. For this reason, it doesn't make sense for spam senders to stick around waiting patiently for unresponsive or slow mail servers.
We have found through our research that slowing down spam traffic provides enough of an economic disincentive to spammers that to cause 90% of them to disconnect if delivery is slowed down by even 10 seconds. We have seen "attrition" rates as high as 97%, and typically in the 85%-90% range.
Subscribe to our blog's RSS feed (unsubscribe at any time).
