Twitter is expanding Birdwatch, its crowd-sourced fact checking project it started as a small and little-publicized pilot program last January. The program lets regular people flag and notate misleading tweets. Starting Thursday, a small, randomized group of U.S. Twitter users will begin to see these Birdwatch notes on some tweets and they will be able to rate them as helpful — or not. The company has said it wants both experts and non-experts to write Birdwatch notes and cited Wikipedia as a site that thrives with non-expert contributions. The ratings, meanwhile, are similar to Reddit’s up and downvotes for comments.