Well, it's said that the application has content filtering. Which is filtered?
There are many categories defined in the net.purum. Network administrator configures, which categories are permitted to access and which are denied.
Page requested for access by browser is checked inside the net.purum/ISA proxy against lists of words/URLs. By this check it's recognised to which category belongs requested page, when it belongs to denied category, website is inaccessible (it is posible to ask administrator to permit specific denied websites). Additionally page is checked for malware presence with avast! engine against avast! virus database.
Is this application similar to www.k9webprotection.com?
Yes, by purpose, but net.purum isn't a desktop application, it should be installed on internet gateway(s).