Mark Zuckerberg's Meta started Threads three years ago. It now says it's up to 500 million monthly active users. I wonder how many people actually know they're posting there. Yui Mok - PA Images/PA Images via Getty Images Meta's Threads says it has 500 million monthly active users. A lot of those people are cross-posting from Facebook or Instagram. Some of those cross-posters don't seem to realize they're doing it. One classic — and sad — example is a woman posting about her husband's death. I