15 years ago this week in 1990 Tim Berners-Lee invented the concept of the World Wide Web as we know it today. The internet at that time had already been around for 20 years at that point, and the concept of ‘hypertext’, a phrase first used by Ted Nelson, was already in use in some standalone applications.
Tim Berners-Lee saw the possibilities of the combination of these technologies, and the World Wide Web was born.
Since then many versions of web browsers have come and gone, and rendering technologies and plugins have advanced (Java Applets and Flash), but the core technology remains much the same, which is remarkable when you think of the pace of change in other areas of technology.
eWeek have a collection of related articles on the origins and development of the web here.