A person addicted to email, myspace, online forums, blogs etc., whom is constantly and annoyingly tap-tap tapping or typing out letters and words voraciously on their keyboards. A emailaholic. The word Tapajawea is a spoof on the name Saqajawea. Only because it rhymes.
"No, thats not rain... its only Tapajawea online answering his emails again." Or, "Tapajawea, please turn the computer off and stop that insessant tapping on the keyboard!" "No, Dr. I didn't bite my nails to the bone, I Tapajawea'd them off while blogging all night" You get the idea!