AddGood is a personal computer. Nelson comments that "it has less memory than his stroked-out grandfather", suggesting that it is extremely old. It appears to reference personal computers from the mid eighties, such as the Apple //e or the Commodore 64.
When Edna Krabappel took away the student's cellphones, Nelson asked her to teach them only the knowledge in her own head. Edna quickly ordered them to play Word Jammers and then started playing the game herself.