For this reason I think the Gizmodo link does not deserve traffic.
Essentially you are allowed to use the rules of DnD (and other games that use the license) to make derivative work as long as its also published with OGL.
It allows homebrewed content to exist and is part of the reason the DnD community is so big.
WoTC (Wizards of the Coast, the owner of DnD) is “updating” the license from 1.0 to 1.1 and is using the update as an excuse to clamp down on competition and limit what can be used.
This has a far reaching effect because 1.0 would be revoked which means lots of content that has already been created would be put in a grey area, WoTC could sue anyone who made content for ownership even if it was made with the previous license.
It also puts entire games like Pathfinder into question as these are essentially modded DnD.
Unless I misunderstand, according to the submitted thread this isn't the case.
>The good news is that, because of the reliance principle, third party creators who have already created a work under the OGL likely could continue to sell that work even if the OGL were revoked. They just could not create any new works.
Although that "likely" gives doubts.
> WoTC could sue anyone
isn't contradicted at all by that opinion.
My understanding (relatively naive, though I am a long time consumre of D&D products) is that Hasbro has been making some questionable decisions recently particularly regarding their golden goose, which is Magic the Gathering. Some of those decisions have really annoyed the fan base, e.g. the Black Orchid debacle (they replublished a bunch of cards that they promised would never be republished, at hugely inflated prices).
In an attempt to shore up their share price and profits, they've reviewed their other product lines to see if there's any slack that can take up the load: which puts D&D in play. The bean counters believe that Hasbro is leaving a lot of money on the table; It's very popular and has had something of a resurgance recently due to popular media like Stranger Things and Critical Role, along with the well received 5th edition.
Ignoring direct IP licencing (e.g. games/movies/etc.), the majority of the revenue is from Games/Dungeon masters (as I understand it, in line with my experience), and not the players. DMs buy the books and run the game. DMs are a fraction of their player base, and there's certainly many who depend on free/open products to save costs. The powers that be believe that some of that can be monetised more effectively and they're trying to think of ways to extract more money from more people.
D&D 5e does fill an important niche; it's the public face of table-top role-play gaming, and it's pretty easy for anyone to pick up and run/play, however it's not the only product on the market and there are many products that serve the customers better (even if they're less accessible and require an understanding of the genre to choose) - Hasbro/WotC have to make this work, and quickly, or they run the risk of losing everything.
Paizo (via Pathfinder) probably has the most to win here; it's well known in the community and has much better support for people who prefer a "crunchy" game. Paizo are probably kicking themselves for not removing their dependency on the OGL when they released Pathfinder 2e (which is what my group plays most frequently).
3.5 was an update released for balance reasons, as I understand it and didn't change core gameplay - it removed some of the more broken exploits, but you can use 3.0 material with 3.5 with relatively few, if any changes: most of the balance problem was player side.
I used to play basic D&D as a child, and then sort of ignored the whole genre until around 2005 when I picked it back up again, using 3.5, so I'm not an expert on it by any means.
In this case, it refers to a large part of the Dungeons & Dragons system, normally kept in books you have to pay for. Wizards of the Coast, who down the D&D IP, decided to "open source" most of the system and a lot of monsters as a way to drive 3rd party engagement. Remove any licensing restrictions, have at it nerds, build a community.
Hasboro has since acquired Wizards (years ago, actually), and has decided to reign in the licensing. Several other games / game systems / publishers are using these open source rules, and it threatens to alter or extinguish that community.