It's hard to prove that people were ignorant, of course, but I think it did bring cryonics up to a lot of people who didn't know about it. (If nothing else, all the kids and teens watching it - the younger you are, the less time you've had to run into the idea.) Some links:

• Futurama hits on Cryonet
• 'cryonics' hits: 535k
• 'cryonics AND futurama': 1,850k
• Ngrams 1960-2008, cryonics & Futurama (apparently 'Futurama' was a term long before the show? So the ngram is a bit meaningless, though it's interesting it has surpassed cryonics.)