One report, that may be related to the drop seen, was posted about a month ago:

The MSNBC link I tried says it's expired. Article title was "Spam host blocked from Net" or "Host of Spam Groups Cut Off" and might be found in Washington Post archives, if anyone wants to search.

[Extract quote]

Junk e-mail drops after providers disconnect a California firm
By Brian Krebs
The Washington Post
updated 11:12 p.m. CT, Wed., Nov. 12, 2008

The volume of junk e-mail sent worldwide dropped drastically today after a Web hosting firm identified by the computer security community as a major host of organizations allegedy engaged in spam activity was taken offline, according to security firms that monitor spam distribution online.

While its gleaming, state-of-the-art, 30-story office tower in downtown San Jose, Calif., hardly looks like the staging ground for what could be called a full-scale cyber crime offensive, security experts have found that a relatively small firm at that location is home to servers that serve as a gateway for a significant portion of the world's junk e-mail.

The servers are operated by McColo Corp., which these experts say has emerged as a major U.S. hosting service for international firms and syndicates that are involved in everything from the remote management of millions of compromised computers to the sale of counterfeit pharmaceuticals and designer goods, fake security products and child pornography via email.

But the company's web site was not accessible today, when two Internet providers cut off MoColo's connectivity to the Internet, security experts said. Immediately after McColo was unplugged, security companies charted a precipitous drop in spam volumes worldwide. E-mail security firm IronPort said spam levels fell by roughly 66 percent as of Tuesday evening.

Spamcop.net, another spam watch dog, found a similar decline, from about 40 spam e-mails per second to around 10 per second.

[end quote]

This was apparently "the big 'un," but there have been a few other "significant contributors" who have been similarly cut off since.

***

So a month is about how long it takes LH to notice something - (?).

Now we have a benchmark for the next test. We'll have to watch and see if he beats this record the next time something happens.

John