You gain ability to transmit message to EVERY human on earth at same time what do you do with it?
//Edit forgot to mention that this is unlimited usage, not one time thing! The message will be a text, that every human on earth will be able to physically see. It'll look kinda like HUD in video game text chats, fading away after set amount of time by you (min 5s, max 5min). You are able to choose font + text color. The message will be automatically perfectly translated without losing the meaning of your words, without error unless you wish to not do so. If the people are asleep while you use your ability, they will dream about the message very vividly and remember it.
Now... The part with more troll potential! You can also choose to put a couple filters, which would make it so you ONLY send the message to certain groups of people.
Age, Gender, Nationality, Profession, Networth, Criminals.
Example: British Men over 30 who are mechanics shall see "I think it's a great time to grab a beer!"