🤑 Indie game store🙌 Free games😂 Fun games😨 Horror games
👷 Game development🎨 Assets📚 Comics
🎉 Sales🎁 Bundles

If sending mail to each other was part of the gameplay experience, I think that could be really cool. Creates a sense of being part of something bigger, of a community, of discovery (depending on game theme) and sharing. Don't know how it would be done, though!