Hooroo is, in effect, Jetstar. Qantas provide the infrastructure, Jetstar earn the revenue.
Say what...
Hooroo was launched in mid-2012 and is fully owned by Qantas.
Qantas launches 'Hooroo' hotel booking and social travel site - Flights | hotels | frequent flyer | business class - Australian Business Traveller
AFAIK Qantas has always operated a travel agency business - remember all the Qantas Holidays stores that used to be around. This business was merged into Jetstet Travelworld and Stella and is now called helloworld and I believe Qantas still has a stake.
As for selling cruises - well often people fly to take cruises - and indeed often book the very lucrative one-way fares - why wouldn't Qantas want a piece of this action