Blingtard is a contraction of bling and retard. And is a response to the over abundance of bling on some persons, thinking that more is allways better.
This word originates from the virtual world Second Life, where one subculture is white boy gangster wannebe's Role Playing gangsters with to much Bling. But since the Bling in RL is getting to absurd levels, the word is starting to being used for RL bling retards as well.
In computer programming used to describe a user interface with lots of bling, bitmapped themes, animated widgets, reacting to user events that should be ignored, more focus on appearance than functionality. Typically unusably slow due to either the effects being too heavy for the machine, or due to animated transitions designed to force the user to watch them fully and exclaim a loud "wow!" as a punishment for clicking or getting near the computer at all.
Hmmmm, KDE isn't yet blingtastic enough, let's add Plasma in KDE 4.0.