You may wonder what Level3 is, but it is a major backbone of the Internet based in the US. Many services and even ISPs rely on it to ensure major parts of the world are connected; in fact everything from Yahoo Mail, PSN, Xbox Live, Outlook, BT, Twitch, HBO Go, Craigslist, and other networks and services rely on it.
Level 3 Communications, based in Broomfield, Colorado, provides Internet service via their Tier 1 network to Internet carriers in Europe, Asia, and North America. This means we will currently see problems with a range of services in the UK, Germany, and United States that all use the Level3 network.
Their website is taking a hit right now as services scramble to find out how widespread the outages are, but as we can see from the Down Detector site, and picture above (taken at 14:00 PDT/23:00 CET on 8/27/15) the red blotches tell a bleak story.