Feature extraction(Hu and Liu, KDD-04; Liu, Web Data Mining book 2007)
Frequent features: those features that have been talked about by many reviewers.
Use sequential pattern mining
Why the frequency based approach?
Different reviewers tell different stories (irrelevant)
When product features are discussed, the words that they use converge.
They are main features.
Sequential pattern mining finds frequent phrases.
Froogle has an implementation of the approach (no POS restriction).