I read your letter about Skitch and would like to respond to all that has happened from my end-user perspective.
I am a long-time Evernote user and fan. Evernote changed note taking by being truly searchable. I can confidently drop all the websites, receipts, todos and ideas in there, and clear my mind of the “I must remember that” burden. The OCR of Evernote works beautifully on photos of whiteboards, making even my whiteboard notes searchable.
In 2010, I discovered Skitch. The simplicity and razor sharp focus on anotating a screencapture and share the anotated image by dragging it anywhere was sheer brilliance. My daily work includes making annotated screenhots and mailing them to team members to discuss improvements. Skitch changed this ugly capture-save-edit-save-attach-send cycle to pure poetry in motion. Dragging images into Evernote even made my screenshots searchable. It instantly became second nature and my go-to image tool.