Jill/txt expertly dissects an ongoing discussion on the distinction between link-driven and content-driven weblogs.
In the end, I think this distinction becomes a chicken-egg argument. When used well, links are content, and content naturally generates links. (Observe, for example, how Dave Winer finds ways to add links to everything he writes about, even when writing about whatever he's thinking about over his morning coffee)
The extreme cases (pure links/pure essays) exist but are uninteresting. The trick is to use links effectively, both in their immediate rhetorical role and also in their long-term, social role in nurturing emergent structure among weblogs.