Your peers. Daringfireball, A very popular blog with readers of this site, gets something like $15,000 per mention in their newsletter.
Now, I know for a fact that the feeds to influence buying decisions for smaller, cheaper stuff, such as cosmetics. It is not a long stretch to think that it also works for vacations. However, from what I heard, the brands that are most successful in selling out their stock are in the category of affordable luxury.