When you write a review only for HonestGamers, and it isn't posted on any other community review site, you can tick "HonestGamers exclusive" in the editor to ensure it reaches more of the site's readers.
Exclusive are designated with a blue badge on the review and in the archives, and they're gathered on the Exclusive reviews page. We love it when you choose to make your work exclusive, though it's never required for reader reviews.