After the broadcast, Orsen Wells told reporters there was no intent to create the chaos that ensued during the hour the play aired. Wells also said he was surprised people would believe there was an invasion from Mars. Years later, Wells told the BBC that he secretly wanted to demonstrate that people were too willing to believe what they heard on the radio and later television. Script writer Howard Koch, who later won an Oscar for the screenplay of Casablanca, reflected Well's sentiment in a PBS All Things Considered interview (Part 1, Part 2). Koch claimed that schools were doing a poor job in teaching kids how to think for themselves.
Could a hoax on the scale of what Orsen Wells pulled off in 1938 happen today. The answer is yes. In fact it already has happened. CNN posted a report that Apple CEO Steve Jobs suffered a major heart attack. This report triggered a massive sell off of Apple stock driving stock prices way down for about an hour before the hoax was revealed. It was later learned a teen posted the fake story CNN picked up as a joke. This story also raised concerns about the validity of "Citizen Journalism." The lesson here is in this day of near instant information, people should check the validity of sources before acting on them.
As far as an invasion from Mars is concerned? Orsen Wells said at the end of War of the Worlds, "If someone rings your doorbell and is not there, it is not Martians. Its Halloween. Happy Halloween everyone.