There are only so many ways to invite specific people into a game. How would one go about inviting forum-goers to a game without knowing their email?

Click "send invite via email" it will have a default email message pop up and give you a link to join the game. You can just copy and paste the join link and post it here for players to join

Or copy-paste it into a Private Message. I'm not sure if it's the default settings or if I check it when I register for a forum, but I get email notifications about PM's.

I wasn't invited. Should I be offended?