The original Main Street Electrical parade ran from 1977 until 1991, then SpectroMagic ran 1991 to 1999. MSEP returned for the millenium celebration from 1999 to 2001. SpectroMagic's final run was from 2001 until 2010. The Main Street Electrical Parade came back once more in June 2010 as part of a limited event called "Summer Nightastic." At the end of that summer promotion, Disney announced that MSEP had been so successful and due to popular demand, they were leaving it in WDW indefinitely. (You might recall that the boards were rife with speculation at the time that this had been part of the plan all along.) Hope that clears it up for you!