How much spam do you (or your company) filter out in a day?
My company (not my web hosting company) filters out approxiamately 10-20 million spam emails a day.
At first we use the MAPS black list at the routers (anything this rejects dosen't get counted as spam). The use a cluster of ironport servers (the email that ironport rejects dosen't get counted into our spam total). Then we have a cluster of birghtmail servers (anything this rejects gets counted in the spam totals).
So if you figure that the first two layer of protection don't count the number of spam they reject we are probably getting around 20-50 spam emails a day (that would be around %60-80 of the email coming into the complex).
