As an example, here is a gag that I submitted to Nickelodeon on July 5th, 2006:
MY werewolf astronaut gag was "banked" (turned in to Nickelodeon, but saved for a later issue) so it did not see print until AFTER Graham's video hit the internet. At first, I was very self-conscious, that people would think I stole his idea, but eventually I realized that this kind of thing happens a lot.
As another example, here was a gag idea that I submitted to Nickelodeon a few months before the werewolf gag, in 2006:
I was pretty surprised when this gag was not approved, because it seemed like a surefire winner. It had a solid DOUBLE pun and a reference to Harry Potter which was at its all time highest popularity. But a month after I submitted this idea, there was a two page spread in an issue of Nick Mag where there were all kinds of characters doing strange things, and the reader was supposed to figure out which movies they were referencing. And there, in the corner, was a Hairy Potter!
Each issue of Nick Mag was prepared many months in advance, so there's no way they could have taken my idea, it's just that someone else thought of the same joke!