The amount of spam hitting users inboxes fell off a cliff in late December, with many attributing the decline to the sudden disappearance of the Rustock botnet and other networks from the spam business. But the level of spam has begun to gain back some of the ground it lost today as other spammers have taken up the slack. The volume of spam took a big jump upward in the last 24 hours, according to researchers at Websense. The spike in spam today appears to be attributable to medical spam using Russian domains that we have seen used before.
Source: https://threatpost.com/spam-volume-recovers-after-holiday-break-011011/74835/