The world wide web was invented in 1990 by Tim Berners Lee, who worked on a NeXT workstation. NeXT computers were quite capable graphically, but used greyscale displays, so color was not initially a significant concern of the developers. The original browser software was called simply "World Wide Web", but it did not get widespread release, since it only ran on NeXT computers.

More popular at the time were Unix workstations running X-Windows, so a new browser called ViolaWWW arose that utilized that windowing system. ViolaWWW made the first use of stylesheets, so it could specify colors, but judging from the screenshots they didn't yet think to style the links in a different color.

Shortly after ViolaWWW was released came Mosaic, also for X-Windows. However, the authors recognized that PC support was crucial, and they also produced versions for Windows, Mac, and Amiga by late 1993. This, plus the browser's better support for graphics, caused interest to explode. The first public release (v0.5) was in January 1993, and elicited a comment from Tim Berners-Lee to have the anchors a different color. By the 1.0 release in late 1993, Mosaic was using blue for its anchor color, as can be seen from the screenshots on the NCSA press page.

By 1994, NeXT computers were full color, and were following the Mosaic convention of blue links on the original World Wide Web browser (screenshot). By late 1994, Mosaic was spun off into Netscape, and was licensed to Microsoft for Internet Explorer in 1995, so the link color conventions were pretty much set by then.