The biggest merger you didn't hear about today
The reasons listed are pretty silly and jaded. The reason the Tumblr acquisition is bigger news is simple: it's a big player in a fast growing economic sector. As big as both Warner Chilcott and Actavis are, their industry is mature. The Warner Chilcott acquisition is unlikely to shake things up. Tumblr is one of the "not facebook" players in social that's gotten a lot of mind share. If and how they can turn that mind share into revenue is important to the sector (and the market).