I pay an industry directory a premium for a "National" listing. On the directory site itself, there is no distinction between the national and local listings -- they all appear in the same section. I asked the people who run the site how they justify the premium -- they said that national listings (landing pages) are "optimized nationally" on the search engines, whereas local listings are only optimized locally.
I understand how a landing page can be optimized for a local market using local keywords, but how can a page be "optimized nationally"? Sounds like a scam -- although the listing is producting results, so I don't want to upset things if their claim makes any sense.