Actually that's signing into your Google account, to use the Market and to sync, etc.
Reactivation is the call to Verizon and press 1 to "program" your phone to use the network, and set the PRL, etc. Your phone will go to the Activation screen immediately after bootup. Press 1 when you hear the Verizon lady and wait till you get the "Your phone has been programmed successfully message."