Metasearch giant Kayak has given in to the inevitable and discontinued its cruise search service, confirms the Priceline-owned company.
Robert Birge, chief marketing officer for Kayak, explained to Tnooz by e-mail:

We've decided to limit our product development to focus on larger verticals.
Launched in 2007, Kayak's cruise search feature aimed at the US audience and was a first in metasearch, allowing shoppers to compare itineraries by price, style of cabin, and departure port.
A rare victory for suppliers in the digital era
Unlike the fragmented industries of air and hotel, the cruise industry has only a handful of players. The major lines have used their consolidated power to retain control over the distribution of their products.
Today, most cruises are still sold offline. A recent PhoCusWright survey found that merely 13% of cruise bookings were made online in 2011. Of those, nearly half were made through websites operated by the cruise lines themselves.
The typical cruise line has a "no-rebate" policy, which makes it difficult for any agency to attempt to undercut it on price as, say, a loss-leader. The agencies only allow offline cruise agencies to sell berths at wholesale rates.
That means that only 7% of online travel bookers booked a cruise component to their trip online in 2012, according to PhoCusWright's Consumer Travel Report, Fifth Edition.
Many cruise sites are mere bulletin boards. Vacations To Go, for instance, doesn't offer direct online booking without engagement with an agent, at least by e-mail.
In short, the cruise lines starved agencies and third-party sites of the ability to present bookable content in an easy-to-compare, commoditizable format that metasearch sites could link to.
Mobissimo, for instance, offers "Cruises" as one of its content options--but the link re-directs to a single travel agency, Avoya Travel. Not exactly metasearch.
Meanwhile Skyscanner, DoHop, and Google are all avoiding cruises.
Industry winners and losers
The failure of metasearch is a gain for the largest online site for selling cruises direct, Cruises.com, which is owned by World Travel Holdings, and the second largest, CruiseOne--also owned by World Travel Holdings.
Despite 8 years of possible competition, these two sites have locked up much of the online direct bookings in cruises.
As for metasearch, that ship has sailed, as they say.
NB: Image courtesy of quinet Flickr/Creative Commons