To keep up with demand and ensure users get quick access to information on the World Wide Web, Internet service providers have been adding capacity continuously, interconnecting more users and companies and at faster speeds. For home users, the progression has seen capacity increase from dial-up (56Kbps) to fiber (1Gbps), while for mobile users cellular speeds have increased from GPRS (~100Kbps) to LTE (~100Mbps).
As with Moore's Law for computing, and despite continuous investment in capacity, we have reached a point where adding more capacity will not necessarily make the Web faster. The fundamental reason is that propagation latency—the time it takes information to travel from one point to another on the Internet—is lower bounded by the time it takes light to travel the same distance, and thus cannot be lowered.