Personas and poker
Dirk Knemeyer brings together two topics I love and the resulting essay is thought provoking. He's absolutely right when he says that personas can be dangerous when they're too shallow. If personas don't document what people really need from our site and how they behave online - if they're merely bulleted lists of demographics that tell us nothing about how people actually use the site - then at best they aren't helpful, and at worst they can mislead. This is why actual contact (!) with users is so important. You can't bluff your way through creating personas, or it will come back to bite you.