I think one of the ways in which I've participated in online crowdsourcing is by answering other people's questions on Reddit. For example, I used to be in the subreddit for Harry Potter (r/harrypotter) as I'm a pretty big fan of the franchise, so whenever someone was unsure or confused about something related to the series, I would try my best to address that. However, I soon realized I was spending way too much of my time on the platform and ended up deleting my account.