You can run this like radio. You can buy the time and keep all revenues, you can share revenues with Twitter, or you can make a certain amount of your time available for Twitter to advertise things.
I suppose so. But unless you are a good salesperson or can otherwise attract sponsors, better I think to just let professionals run the ads for you. One hitch might be some sponsors are afraid to be affiliated with certain content. Another hitch would be timing. I hate watching youtube videos when they drop an ad in mid-sentence. At least traditional outlets have a schedule so you know to plan for a break... or maybe the video makers don’t know to insert a break for ads, or maybe youtube doesn’t use regular timed intervals that programmers can work off of.
Elon Musk just made the offer - I am not sure how it works. He was trying to attract content creators to publish on Twitter - anything from written word to audio to video and maybe more like pure play long form sales programs though few I think would knowingly tune into a 30 minute long ad. And yet, they do run on TV.