The expected thing in standup is that your jokes must be original. In practice, this means you write your own jokes. Joke theft happens but can be career death.
There are four scenarios under which a standup might tell jokes written by others:
- Legitimately paid for them. This is standard fare in cases where it’s simply impossible for the comedian to write enough material - late nnight talk show hosts being the obvious example. No comedian who ever lived could write that much stuff themselves, so in such circumstances your Stephen Colberts and Seth Meyerses must rely on staff writers. It is worth noting that in such cases, those men personally choose who they hire, because the writers’ senses of humor need to work for the comic. Seth Meyers personally manages his writers; he doesn’t personally manage the camera operators.
It is also common for comics to give one another jokes or sell them for small amounts. I was given a joke by another comic because it was funny, but he just couldn’t find a way that it made sense for him to tell; I reciprocated with a few good ones I thought worked well for him. Later on another guy wanted to give up comedy and offfered to sell me his best material for a small sum; we never got around to formally doing it, and he sold them to someone else.
- Stole them. The great majority of comics do not steal jokes but there are a lot of comics, so it’s not uncommon. There are some famous examples, of course, like Carlos Mencia.
Some comics will inadvertently steal jokes; comics love to watch comedy, and between watching a huge amount of comedy and and then brainstorming and writing loads of your own material, you can do this accidentally. Robin Williams was famous for this (a problem exacerbated by his improvisational style.) To his credit, when it was proven he’d swiped a joke, he would customarily pay the aggrieved comic very good money for it.
- Accidental repetition. It is quite possible for one comic to tell exactly the same joke as another quite by chance. I mean, how many different jokes about big dicks are there? I had a joke about getting old and my testicles hanging really low, and one night when I was the middle act, watched in horror as the opening act - a guy I’d never met before in my life, who could not possibly have seen me perform - told the same joke. I had to change my act on the fly. I am totally certain it was just coincidence. Flying around out there are many of the same jokes about dicks, airline food, Donald Trump, why your kids drive you crazy, traffic, sex, so on and so forth,
If you’re wondering how one tells the difference betwene accidental repetition and joke stealing… I mean, 99.99% of the time it’s really obvious. It’s gonna be either the same basic joke on a common theme with variations in wording, or it’ll be a joke that clearly was ripped off. If I do a simple, generic joke about the size of my wang, no one will think that was ripped off from some other guy. If I do a routine where I specifically say that houses are just a place to put your stuff and “your stuff is shit, but my shit is stuff,” I clearly ripped off George Carlin. The wording is too specific. If I tell a joke about how buffets made me fat, whatever. If I go into a spiel where I suggest ordering from a real restaurant what you’'d eat in a buffet and carefully descbive three overloaded plates of food, say “yes” to the dessert menu, and a ridiculous number of beverages, well, I ripped this off, right?
- Telling street jokes. You will from time to time see a comic in a club telling “Street jokes” - jokes so common, that have been around for so long, that you can’t really say they were stolen from a particular person. They’re just old jokes.