Neural network for theme recognition in twitter

Tweets -> Normalization -> Label -> Train Neural network -> Works for just 1 theme?
                |-> POS Tagger
                |-> Unsupervised Learning
                |-> Ontology

¿Clasificar en base a la estructura? ¿En base al contenido?

Automatic labeling? -> Entity Relationship? -> Clustering?
                                  |-> Web n-gram?
                                  |-> Wikipedia?