It's a problem every web user has struggled with: trying to visit Facebook or Twitter, only to have Safari take forever loading or Chrome spin its wheel. Fortunately, there are a couple easy ways to find out if Instagram, Snapchat or any other website or service is down.
The first is visiting downforeveryoneorjustme.com, also accessible from isup.me. The site displays a simple text box, where a user can enter a URL like "gmail.com." The site then checks to see if the page loads when accessed from its servers. If Facebook loads from there, it might mean the social network isn't down but rather the problem is with the user's internet connection. If it is down, an error will display.
The other option is DownDetector. This covers services that aren't accessible from the web, like the PlayStation Network or Microsoft's Xbox. If Xbox Live is down, DownDetector will know. The site collects reports from all over the world, showing a live heat map of where reports are coming in from.
The website in question may also host its own service status page to keep customers informed of any interruptions. Searching the name of the service followed by "service status" may answer the question, like "Xbox Live service status" or "iCloud service status." This will be of little use, though, if the website isn't loading to begin with; it will be more helpful for checking the status of services like PlayStation Network.
Companies may also update users on their Twitter feed. Search for a company's user name on Twitter, keeping an eye out for that blue "verified" mark that indicates the account has been approved as real by Twitter. Of course, if the question is whether Twitter is down, that won't be very useful. Instead, Twitter has its own status page.