Facebook is trying to buy its perceived competition, i.e. the "next" Facebook before it can actually become The "next" Facebook. Same thing as with Instagram.

Facebook is trying to buy its perceived competition, i.e. the "next" Facebook before it can actually become The "next" Facebook. Same thing as with Instagram. The fact that they can spend so much money on this (and that their investors allow it) shows just how much they want to remain on top.