Yahoo Pipes

Yahoo Pipes was a web app in which you built data flows by dragging pipes between blocks — fetch an RSS or Atom source, filter it, merge, translate, and emit a new feed. The name nodded to Unix pipes, and the idea was mashups for everyone: programming without writing code.

Yahoo launched it in 2007 and it quickly became a favourite among the technically minded, but it never reached a wide audience. As the heyday of XML feeds ebbed and Yahoo trimmed its sprawling product line, Pipes was shut down in 2015. It's often cited as an early, rare success at visual programming on the web.