9 Ways to grow a massive following on Twitter from Kimba. From Glen, way back when, like pre-Y2K, a few credit card companies offered virtual card numbers, one-time-use cards that would allow us to "safely" buy things from that new thing called the Internet. Fast forward to 2009, and more companies like PayPal and some banks offered these too. We'll take a look at where things are today, now that companies have the all too common problem of customer databases being hacked and the info sold globally.