Check out this misleading graphic:
A monthly audience of 280,000+ is pretty amazing considering there may not be that many people in the entire industry.
The footnote though keys you in on the trick:
NO ATTEMPT HAS BEEN MADE TO IDENTIFY OR ELIMINATE DUPLICATION THAT MAY EXIST ACROSS MEDIA CHANNELS.
First of all 'unique browsers' and 'page impressions' are the exact same 'media channel'. Page impressions are simply the actions a browser takes. Adding them up is comical, resulting in a wild overstatement. In particular, 40% of their claimed 'audience' is not an audience but the erroneous insertion of page impressions. Under that logic, IPVM has an 'audience' of 450,000 just on our 'page impressions' alone.
Similarly, there is significant overlap among their 3 newsletters, which Security Sales should easily be able to determine, but they simply add them all in, to make it look better / bigger.
Normally, I would not even look at this but we are in the process of updating our IPVM For PR / Marketing People post so I was verifying recent industry stats.
For the record, Security Sales claims 57,849 monthly visits and 112,542 page views. IPVM has nearly 3x that of monthly visits (150,000+) and nearly 4x that of page views (450,000+ a month).