I just posted this to http://ixda.org.  Thought it would be worth saving.

In response to the question: what is a Landing Page?

I think that the main purpose of a landing page, from a user's perspective, is that it's a payoff page.  It says to the user, "Oh, I've arrived somewhere." It is a temporary respite from the transitional pages (or links) that got them there.  A home page, through the lens of this thinking, is a very special landing page.  Business unit pages can be landing pages.  Special pages associated with online campaigns are landing pages, too. This gives a bit of direction to the design: how does one communicate, through subtle or not-so-subtle page design, that "you have arrived" ? It's this direction that has informed and inspired my designs.