[prettyrandom100]

Since IP filter will rule out many sensitive contents that is said about corporation, government, I'm fairly certain it can be ruled out as a good indicator of spam. If it is a spam, is it that hard to just look at the content, I think not!

[tobylane]

Strongly anti- (or pro) corporation and government posts will be dinged by the filters. I forget the exact names for them, they exist to reduce arguments.