When the activist fund Starboard launched an attack on Yahoo! ( YHOO ), it was just one of the many recent takeover targets. Continue Reading Below Noted activist investor Bill Ackman has launched attacks against Herbalife ( HLF ) and embattled drug company Valeant ( VRX ). Starboard previously launched attacks against Olive Garden's parent company ( DRI ). So what's the activist investor epidemic plaguing boardrooms?