OK as this Blog's Mr Contrary I would like to throw this into the fray...
I don't believe the Web is one-to-one.
Ad agencies and marketing gurus and even the esteemed Mr Locke state that the Web is "one-to-one".
My contention is that there is SO MUCH one-to-many communication out there it merely appears to approach one-to-one communication. Therefore, the term is a misnomer and slows down development because content providers delude themselves.
I will concede that there are many places where interests coincide; where like minds meet. However, one-to-one communication is face to face and no more. There needs to be true interactivity - listening, even - from a Web site before I will admit to one-to-one communication being present.
Unless you know different...