Overly preoccupied with the approval or disapproval of one's contributions to a website on the Internet. May also refer to a group of Internet users who share this preoccupation. It is not unusual for a person with this obsession to also be a thumb whore or to describe the pain of "thumbs down" in order to rant about their shortcomings. Those who do so are typically not regarded as thumbcentric by the general population, however, as it is clear that they are only retarded.
Once Bud visited urbandictionary.com, he knew his definition was getting ripped a new one, so he chucked the monitor through the sliding glass door. Bud was a little thumbcentric.