Knowing your donor means knowing what they want from your organization and letting them get to know you. A variety of strategies are being used to accomplish these goals. Allowing for donors to have online personal profiles kills two birds with one stone (suggested by Sheeraz Haji in his article, They're Doing What?).
Not only can they update their own contact information, but it is also an open outlet on which they can submit information about themselves. The information collected could give great assistance towards understanding who your donors are and what they are interested in.