At Bob Kraft's request, I am going to sketch here one advance that has been revolutionary for me and for others. The first principle is that the great research libraries of the world have been and are continuing to make their collections more accessible through computer cataloguing. Most major university collections now have at least part of their collection in an on-line catalogue and most users are now accustomed to looking not only in a card catalogue but also in one of a row of terminals usually found standing in the entrance hall of the library. The second principle, specific to the world of computers, is that any information in any computer anywhere in the world is theoretically available to any other computer anywhere in the world, including the one on your desk. In practice, there are often obstacles, but happily librarians genuinely enjoy minimizing those obstacles.
Many exciting developments remain, but much has already been done.
From any modem equipped telephone anywhere, you can now reach a huge variety of library catalogues. I grew up in New Mexico and Texas. The Penn library doesn't have it on-line. You also need to know less about library cataloguing and filing conventions than you used to, and that can be a great time-saver in obscure cases. Perhaps the most important use, however, is for gaining access to catalogues better than that which your home institution can offer.