World

"Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives." — Carl Sagan

Everything.

Geography

• List of Reddit subs by country and territory
• List of Twitter hashtags by country and territory

Language

• List of Reddit subs by language
• List of Twitter hashtags by language