Mostly used as an Internet term. A descriptive used to define someone who is always looking to learn new information. The junkie part comes in when they seem to be 'addicted' to any new information. Frequents news sites, technology journals, reads many books, and seems to understand all this. Chosen topics of interest can be varied. Usually a first point of contact when your computer breaks or you're thinking of signing up to make money online for only a $500 deposit.
He's such an info junkie!