Yes, you can still book a future cruise with Carnival, but you can no longer book a future cruise certificate. The difference is that with a future cruise, you have to select a specific cruise and with a future cruise certificate you don't - you can wait to decide at a later date.
If you know exactly what you want, then it's still a good deal - you just don't have the flexibility that a future cruise certificate offers.
Travel Agent/Cruise Specialist w/12 yrs exp and 47 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!