hedwards: The EU likes to think that they can do things like that, but it would be chaos if we started to allow one nation or region to write laws that were applicable to people with no ties to the region.
There are ties though. As wpegg has stated, GDPR does protect EU citizens so even if it's a US (or whatever) company, it has to comply because it is doing business in the EU.
As for the enforceability...I would certainly love to see a case about this, or better two, one company with a commercial interest and one without.
Lucumo: Pretty sure the content isn't yours anymore after you press that "post" button. (I think) GDPR would require the people in power to delete your personally identifiable information which means email, nickname, IP addresses of posts and other such things. So what could remain would be a placeholder called "guest" or something for these posts. Other forums handled it like that way before GDPR was ever a thing.
richlind33: That's the crux of it, IMO, because you've published it in the public domain. You probably should be able to make claims re *specific* data, but in toto?
It's not the public domain. Forums usually have TOS like this one:
"By registering an account at X and participating (including but not limited to submitting posts or private messages on X), you hereby grant X and our licensees, distributors, agents, representatives and other authorized users, a perpetual, non-exclusive, irrevocable, fully-paid, royalty-free, sub-licensable and transferable (in whole or part) worldwide license under all copyrights, trademarks, patents, trade secrets, privacy and publicity rights and other intellectual property rights you own or control to use, reproduce, transmit, display, exhibit, distribute, index, comment on, modify, create derivative works based upon, perform and otherwise exploit the messages posted or private messages sent on X, in whole or in part, in all media formats and channels now known or hereafter devised, for any and all purposes including entertainment, news, advertising, promotional, marketing, publicity, trade or commercial purposes, all without further notice to you, with or without attribution, and without the requirement of any permission from or payment to you or to any other person or entity."