In the world of software, it's not unusual for things to get delayed. But for a project called Xanadu from Ted Nelson (who created the term for hypertext), that delay has spanned five decades, and could have led to the underpinnings of a very different internet if it had been completed sooner, or at all.

The project was originally created to help links sources within documents, embedding them alongside the work you're looking at. In Nelson's working example, which went live in April and was spotted by The Guardian, you can go down a page and see the eight other documents where sections are sourced from. Clicking on any will take you there without leaving the main document. What may seem like a very fancy bibliography was conceptualized as a way to organize vast troves of information and media from disparate sources, as well as keep it from breaking when links were changed.

"We screwed up in the 1980s."

"We foresaw in 1960 that all document work would migrate to the interactive computer screen, so we could write in new ways," the project's page says. "We screwed up in the 1980s, and missed our chance to be world wide hypertext (the Web got that niche). However, we can still compete with PDF, which simulates paper, by showing text connections." But there's still more work to be done before that can happen, including server integration that will let other people create their own "xanadocs," as well as support for media like photos and audio files.

Up until this working page, Project Xanadu was (and still is) considered the most-delayed software ever. In a 1995 feature story, Wired referred to it as "the longest-running vaporware project in the history of computing," adding that Nelson and his fellow developers had "set a record of futility that will be difficult for other companies to surpass." That claim could very well be right, but we won't know for sure until Xanadu is fully-baked. Whenever that is.