On Tuesday morning, much of the internet was inaccessible. If you tried to follow your feeds on X, or engage with ChatGPT, you were only met with error messages. Compare those error messages to one another, however, and you'd likely notice a similar name affixed to them all: Cloudflare. Cloudflare's massive Tuesday morning outage had sweeping implications for much of the web. While it's not clear what caused the outage at this time, we do know whether the outage was responsible for a website's downtime. (When an error page says "Cloudflare: Error," it's not difficult to track down the source of the problem.) As Cloudflare offers web infrastructure services to a huge number of sites, the true list of affected sites is likely massive. As an example, I wanted to convert the timezone Cloudflare uses in its status reports, UTC, to ET, and the first website I clicked on in my Google search returned an error. While there's no central repository listing each and every affected website, we can look at the sites with the largest number of user reports indicating issues this morning through Downdetector. (Disclosure: Downdetector is owned by Ziff Davis, the same parent company as Lifehacker.) Ironically, Downdetector itself was down this morning—it too uses Cloudflare.Downdetector is not a service that investigates and reports websites that are down. Instead, users can self-report issues with sites on Downdetector. As such, it can be illuminating to see which sites visitors were having issues with during the period of time Cloudflare was down. At this time, that includes the following:XCloudflareOpenAIChatGPTGrindrArchive of Our OwnAWSSpotifyLeague of LegendseClinicalWorksQuizletUberCharacter.aiCanvaClaudeVaroIndeedProcoreTruth SocialFanFictionArloDoorDashValorantRunescapeDayforceNJTransitSniffiesSquareGoogleZoomRoverCollegeBoardLetterboxd Bet365MoneyLionDayZBetMGMYouTubeMicrosoftIKEASunoMicrosoft 365Canvas by InstructureMicrosoft TeamsAmazonGrokInstagramGeminiAgain, this list is not definitive, nor is it official. However, users had trouble accessing them at the same time Cloudflare was down.