It's a secret satanic incantation that, if listened to backwards, will summon the demons of hell to wreak havoc among the living, most specifically those of the Antarctic persuasion. OR It's a remix album produced by Mike Shinoda and worked on with the other band members and special guests to put a new twist to their music.
as the name suggests, a "reanimation", with tracks closer to being original tracks than remixes, with so much newly written material on it. i would say it's very experimental.
I think they called Reanimation, because LP and others artists gave more power and a new life to the songs of the Hybrid Theory.
Reanimation is a remix album of Hybrid Theory, with some decent tracks, but it's not all that great. What do you expect out of remixes anyway, all they are, are a stall to make money.
A great re-interpretation of a lot of songs mostly from Hybrid Theory (a couple could have been better though).