There is a ton of psychology at work in Apple's new virtual assistant Siri and if they succeed, it will be much harder to change phones.
The Siri group, one of the largest software teams at Apple, fine-tuned Siri's responses in an attempt to forge an emotional tie with its customers. To that end, Siri regularly uses a customer's nickname in responses, as well as those of other important people and places in his or her life.
For Siri to be really effective, it has to learn a great deal about the user. If it knows where you work and where you live and what kind of places you like to go, it can really start to tailor itself as it becomes an expert on you. This requires a great deal of trust in the institution collecting this data. Siri didn’t have this, but Apple has earned a very high level of trust from its customers.