"Yesterday's blackout was scary. Were you scared? :)"

Your phone vibrated with yet another message from the mystery man who texted you every day. You referred to him as Smile because of the smiling emojis he would send no matter the situation. It was scary, but you learned to appreciate his positive online company. Smile was weird and commented on random things, like now. The problem was, the blackout only happened in your building.

How did he know that?