I just visited an IP analysis site, and it indicates that the OS used by a.webwise.com and b.webwise.com is the F5 BIG-IP. I just googled and found the product:
http://www.f5.com/products/big-ip/
"Our ground-breaking platforms deliver unmatched power, dramatically improving Layer 4-7 traffic throughput and providing better application delivery. F5's revolutionary TMOS architecture is at the heart of all BIG-IP platforms, efficiently isolating clients from the server-side flows to increase application performance and allow custom payload inspection and transformation capabilities with iRules."
Also the link for Wiki:
http://en.wikipedia.org/wiki/F5_Networks
"
Add-on modules to F5's BIG-IP family of products offer email filtering and intelligent compression to allow for lower bandwidth and faster downloads in addition to load balancing and local traffic management capabilities."
The hilighted area above does not make me feel comfortable....