I couldn’t figure out what “Personalization Services” were. What kind of name is that for a $2.1 billion industry? Here’s the English-language definition, via Garnter’s PR team: “The ringtones and ring-back tones that consumers pay for to use on their mobile devices. Typically, these can be acquired directly from service providers and synched to the mobile phone over the air, or can be acquired via a PC or connected device and then synched to the mobile phone.” To sum up: More than 10 years after Napster, one of the key pillars of the music business is ringtones, a business that peaked around 2005, when some of you would have recognized the image at the top right of this post. If you’re reading this, you probably haven’t paid for a ringtone since 2007, and you probably don’t know anyone who does. But there it is, generating two-point-one-billion dollars.