Casual use of drug terms

I often describe a several of my (harmless, I think) activities as "It's like being a crack addict." I have no idea what using crack (Etymology: From its preparation by breaking cocaine crystals into pellets. Middle English craken, from Old English cracian -- essentially, from a word that means a harsh crowing sound -- like the sound of something cracking.) is like, but, I will describe my habit of downloading books onto my Kindle or buying shoes and tote bags online from Zappos as "It's like being a crack addict," which is to say, highly addictive. It's hyperbole, of course, but gets the point across. We all know about crack addicts. In the same way, when the Blackberry was first introduced, it was slangily called the "Crackberry," because you couldn't stop playing with its many features.