> Which will simply be filtered out

These were the last words of the database admin before he went stark raving mad...

But seriously "filtering out" is a goddamnd hard problem, if the dimensionality of your problem space is high enough. You are talking about filtering out sockpuppets like if they have a tcp-flag on it. Even the best trained Neural Network can only work as good as the input-training parameters, and classifying large texts in natural language is still one of hardest problems (even for humans).