According to the FAQ A-Bot "Sorts and ranks Audio files submitted to the Audio Portal, and picks and highlights weekly winners."
According to his Userpage:
Persona and style
A-bot was created to manage the Audio portal in 2003. He writes with a hip-hop style and appears to hang out with Darnell from the Pico series.
A-BOT appears on the Audio Portal page as the big green robot, with massive speakers in his legs.