Blue is arguably the most-clicked color in history. Search results, citations, menus, this very sentence's relatives — for over three decades, an unvisited hyperlink has appeared, almost everywhere, as blue underlined text. Nobody voted on it. No web standard requires it. The choice was made in a specific stretch of 1993, inherited by nearly every browser since, and defended afterward by practical advantages nobody planned. The fullest forensic account, presented by researcher Elise Blanchard at the ACM Web Conference, traces the color through surviving screenshots, release notes and emulator sessions — and finds the story is older than the web itself.
Blue's advantages were never primarily aesthetic. Against the mid-gray and white backgrounds of early screens, a saturated blue was dark enough to read clearly while staying unmistakably different from black body text; red had already been claimed for active or highlighted states, and a blue-red pairing survives red-green color deficiencies far better than a green-red one would. Interfaces live and die on exactly such small contrast decisions — the same territory where quietly failing light-gray text shows what happens when the contrast budget is overspent.
Contrast arithmetic made blue especially defensible. Body text on those early gray desktops was black; a link had to separate itself from black at one extreme and from the background at the other, across whatever monitor the reader happened to own. Blue sits in a sweet spot: dark enough against a white or pale-gray page to stay readable, far enough from black on the hue axis to be recognized in a single glance, and light enough in its default shade (#0000EE) to survive the dim, uneven CRTs of the era. A green or teal link would have collided with green screen traditions; purple read as something else entirely. Blue had the fewest enemies.
What 1993 actually decided
The web's first browsers marked links with underlining, not color — text terminals had no color to give. The graphical age opened with a scatter of choices, and then settled fast: Mosaic, released in 1993, and the other major browsers of that year — WWW, MidasWWW, and ViolaWWW in its headings — were showing blue links by the end of it. Blanchard's most striking discovery is that the decision was not even fresh: controlled experiments in the mid-1980s, eight years before Mosaic, had already been testing blue and cyan as link colors in hypertext interfaces. The browsers of 1993 were confirming an old research habit, not inventing one. Within a few years the convention had crossed the Atlantic and the Pacific at the speed of software installs, arriving in classrooms and offices as a fact of nature rather than a decision anyone remembered making.
What followed is a textbook case of a convention freezing. Once blue meant 'clickable,' users carried the expectation from browser to browser, and site authors could rely on it. Competing colors would have spent each page's first second re-teaching what blue already taught. So the palette standardized sideways, through inheritance rather than decree — much the way the red notification badge became the universal symbol for 'unfinished business' without any committee anointing it.
What the standard says today
The neat irony is that the web's living standard does mention the colors — as suggestions, not commands. The HTML Standard's rendering section, which describes how browsers are expected to present unstyled pages, still lists the defaults the first graphical browsers established: unvisited links painted #0000EE, visited links #551A8B, a dark purple, and active links flashing red. Every browser shipping those values is maintaining a museum piece with perfect provenance — a 1993 color trial still on daily duty, quietly distinguishing the pages you have read from the ones you have not.
That blue-versus-purple distinction is subtler than it looks. The two hues are close cousins separated mostly by lightness and redness, and noticing the shift at a glance is a small feat of rapid color discrimination — the kind of split-second judgment our Speed Color Match game exercises directly. Most readers sense the difference without ever naming it: the link looks 'used,' and their eye moves on.
Designers inherit, then decorate
Modern sites restyle links freely, and well-designed ones keep the lesson: whatever color replaces blue must earn the same trust — distinct from body text, readable on its background, and consistent across the site. When a design breaks the blue convention without offering a replacement cue, users simply stop recognizing links; the underline, blue's loyal deputy since the terminal era, often carries the meaning alone. Thirty-plus years on, the fastest way to make text clickable in a reader's mind remains to make it blue. That is not a law of nature. It is a habit with a birth date, and the birth date is 1993.
The habit now outlives the technology that made it. Phones stripped away the underline to save pixels and discovered users still expected colored text to be interactive; dark modes re-tint blue toward lighter, dustier shades so the convention survives on near-black backgrounds; and accessibility guidance effectively ratifies blue's old head start, since the contrast and colorblind arguments that favored it in 1993 apply with equal force to any successor. A designer choosing a link color today is not making a free aesthetic decision in a vacuum. They are negotiating with thirty years of reader training, and the readers, on average, win.