Sidefari for iPad
As someone who works primarily from an iPad Air 2, I love the Split View feature that came with iOS 9 but it does have its limitations — namely, the inability to run two instances of Safari side-by-side.
Thanks to Federico Viticci, I recently discovered a clever iPad app called Sidefari that has one major purpose: It takes advantage of iOS 9's Safari View Controller (which many developers have implemented for their in-app web views) to let you view a second webpage alongside the main Safari window. Obviously not everyone needs this sort of thing, but for those of us who do, Sidefari is a godsend.
Get it for $1 on the App Store.