Clipboard
I'm not sure if clipboard with the copy-paste concept first appeared in Windows or another OS, but it must have been some 30 years ago. Clipboard has been one of the fundamental UI pillars of multitasking. Then came iOS and Android to kill it, by offering the "share to" replacement. Which could hardly be considered an improvement. And now clipboard is back. At least in the iOS. I'm not exactly sure when it came back, but it is firmly present in the form of a "paste" key on the on-screen keyboard. As is the "copy" option in the "share" menu. And I simply love them both. Android has been long praised for its more flexible application sharing bus. But it is far cry from the iOS copy-paste option. Rediscovered 30 years after the original one :) The most frequently used scenario for me is screen-scrap sharing. Press power+vol_up to capture a screenshot, crop it, share->copy, delete. The cropped tile is in the clipboard now and can be pasted...