Hi,

I'm working on a project to mine feedback comments periodically.  The main goal is to discover new topics or problems from these comments. New to this, I read through several paper and I understand how to use text mining techniques to get topics... but... I'm wondering, what is the best way to classify comments (or documents) into several known topics and how do I get the unknown topic automatically? Say I need to run it every week. 

Any help is appreciated.

Thanks a lot!!

Deborah