||A low-cost wireless electronic learning tool called the Personal Response System (PRS) that facilitates active engagement in a large class by enabling each and every student to answer questions in private was developed and made available for campuswide usage at HKUST in 1998. Its unique features include 1) student transmitter handsets tagged with a 9-digit ID, 2) this 9-digit Student ID accompanies the signal sent each and every time the student presses his/her handset to answer a question, and 3) a handset having a 10-digit keypad plus two additional modifier keys providing a selection of 30 different answers. This combination of low-cost, unique features, and campus-wide applications provided the impetus for making PRS available outside the HKUST. Today, six years later, the large scale adoption of PRS can be found in North America including in such institutions as the University of Massachusetts at Amherst, Harvard University, North Dakota State University, Arizona State University, University of California at Berkeley, Oregon State University and University of British Columbia. Early users in the UK are the University of Strathclyde and University of Glasgow. Other users include institutions in Germany, Italy, Greece, Turkey, Australia, Indonesia and China. Here we review the factors that contributed to its recent widespread usage and the developments that could further increase its popularity.