It is basically impossible to play Dungeons & Dragons without "creating content". Even if you play an official adventure or campaign module, the DM always needs to flesh things out. And of course you might want to invent your own adventures. As long as that happens within the confines of a single gaming group, this process doesn't involve licenses or lawyers at all. But of course some people who did create content for Dungeons & Dragons then wanted to share that content further. And as D&D content doesn't make any sense without referencing D&D intellectual property, you can't legally publish and especially not make money of that sort of D&D content without the permission of Wizards of the Coast, the owner of the D&D IP.

In the very early years of the internet, when D&D was still owned by TSR, they were infamous for aggressively going after anybody even publishing free homebrew D&D content on Usenet. Which turned out to be not a good idea, because they basically destroyed free advertising for their game. By the year 2000, and the third edition of D&D under Wizards of the Coast ownership, it had become clear that some sort of legal framework was needed that would allow players to put homebrew D&D content on the internet. Thus Open Game License was born. Wizards of the Coast provided a "system reference document" SRD, which was basically a rules version of D&D that was compatible with the D&D rules that WotC published, but without the "product identity" of specific WotC material. For example the D&D rules had "Melf's Acid Arrow", but as Melf was a specific character owned by WotC, the SRD just had that spell as "Acid Arrow". While WotC published 4th edition D&D under a more restrictive "game system license", they went back to the OGL with 5th edition.

Now for much of my time with Dungeons & Dragons, the OGL meant that both players and small publishing companies like Kobold Press could legally publish D&D adventures and homebrew rules. That was no big deal, as this was all very much niche stuff and didn't involve large sums of money. But these days companies like Critical Role playing D&D on Twitch and YouTube make millions of dollars every year. And while there is some collaboration between Critical Role and WotC, it is easy to see why WotC would quite like to get some licensing fees from Critical Role rather than allowing them to operate under a free license. Thus OGL 1.1 makes a big difference between publishing non-commercial D&D stuff, and people making more than $750,000 a year from D&D content. And it specifies that the OGL “only allows for creation of roleplaying games and supplements in printed media and static electronic file formats. It does not allow for anything else, including but not limited to things like videos, virtual tabletops or VTT campaigns, computer games, novels, apps, graphics novels, music, songs, dances, and pantomimes.".

Thus a lot of the D&D stuff already out there, like the PC game Solasta: Crown of the Magister, or various YouTube videos, aren't covered by the new OGL, and need some other license to operate under. Which might cost them some money. On the other hand, WotC is unlikely to go after every person making a D&D video on YouTube. This is further complicated by this all being contract and IP law, which is notoriously difficult. You can write *anything* you want into a contract agreement. You and me could make a contract in which you sell me your soul. But that would just be a piece of paper, as I don't have the technical means to actually harvest souls. Yet! :) In the case of the OGL there is a lot of discussion in how far WotC can actually change their original OGL, as it contains words like "perpetual". Different people with different degrees of legal experience have different opinions on that, but before a case comes in front of an actual judge, I would say the matter is somewhat undetermined. Nevertheless, if you are a small scale YouTube D&D content creator, and Hasbro sends a copyright infringement notice to YouTube, your channel is likely to get taken down without a court case. And it would be very expensive and time-consuming to reverse that. Thus the large number of D&D YouTubers who are currently so unhappy and posting videos featuring actual lawyers.