This Pattern is based on the idea that people are more likely to take their contributions seriously and put more care into what they write when their identity is associated with it. This is the obvious case on corporate wikis, but not so obvious on public ones.
IdentityMatters is used to build a community where people know they are collaborating with other people, and will value their interactions just as they would in real life.
Anyone can contribute to Wikipatterns, but to do so you must create an account which involves entering your name. Someone could enter a pseudonym or even a fake name, but most people will enter their real names to have their work credited to them. For those who enter a pseudonym, that can be just as important to them as their real name, as some people work hard to cultivate a reputation for their online identity.