[T]he "personalized newspaper" assumes that people are best served if
they are given news on topics that they preselect. Such a model
neglects how difficult it is for people to know and describe what they
want.... It also neglects the importance of serendipitous news -- news
that people didn't set out to find -- to the way people understand the
world.
-- John Seely Brown and
Paul Duguid. The Social Life of Information. 2000.
p.218-219