The phrase "to catch on" means to understand or realize something, often after a period of confusion or uncertainty. It can also refer to accepting an idea or trend, or becoming aware of something that was previously unknown.
Don't worry, eventually the tiger did find a good home (also in a hilarious way), but sadly I did not catch it on camera. (stillbeingmolly.com)
Leading into the nominations announcement, it was beginning to look like «Another Year» had not caught on in time to register at all. (incontention.com)
That said from time to time they're going to make mistakes, and if they're unlucky it'll get caught on camera. (wtf1.com)