An UberNerd, Tanta tells us, is
someone who is compelled to understand how things work in grim detail, even if the things in question are tedious in the extreme, like mortgage insurance policies.
A Compleat UberNerd is then
Someone who has read all these posts already and quotes them at tailgate parties.
She kindly provides all the links necessary to become the Compleat UberNerd over at Calculated Risk.