• Richness of the annotation • Shallow NLP

• Porting to new domains or applications is expensive • Current technology requires IE experts • Expertise difficult to find on the market • SME cannot afford IE experts • Machine learning approaches • Domain portability is relatively straightforward • System expertise is not required for customization • “Data driven ” rule acquisition ensures full coverage of examples Problems • Training data may not exist, and may be very expensive to acquire • Large volume of training data may be required • Changes to specifications may require reannotation of large quantities of training data • Understanding and control of a domain adaptive system is not always easy for non-expert