Forum Data Analysis

I'm working on an expert system that analysing data from a Forum and get some trustable informations , then i'm using these information to learn my expert system .

The question is How to extract data that give me 90% trustable data if only about 50% o开发者_高级运维f existing data on the forum is true ?! and what is the best resources about forum data extraction ??

I searched a lot about this topic but i've got nothing ,mainly because of its bad keyword "forum" !!

thank you