Sounds strange... Spam flow is 'normal'. What we would like to see is 'gone', but that won't happen as long as the spammers can make money.
As I mentioned last week, there was a large wave of spam the last few weeks. And as expected the wave subsided.
Whether it was the filters that finally caught up to the spam tricks, or if the spammers just stopped, I don't know. I suspect it was a large botnet spamming from a bunch of different infected PCs, but I haven't seen anything in the news yet. (the geek news, of course, since normal news doesn't notice till much later).
Some of the spam news I was researching seemed to only report on 'caught spam', which doesn't give a clear picture. My own filters were not seeing an increase in spam, and that's because it wasn't 'seeing' the spam. duh. Instead, I noticed users were getting more spam in their mailboxes, and I noticed an increase in total mail volume.
Total mail volume on my servers in May increased between 20-60%, but the spam filters don't show the same increase for 'caught' spam. However, towards the end of this week, volume suddenly dropped back to April levels, and more importantly users are noticing less spam. I'm noticing the same drop in Google App's Postini service.
So, it looks like we all have a reprieve from spam for a while, until the next wave of attacks.