The best tools do one thing very well. It nails a certain activity to the wall and really makes it simple and easy. Hammers drive in nails. Del.icio.us saves bookmarks. Netflix sends you movies. Photoshop enables image editing. iTunes plays music, etc. All of these tools actually have other uses, but that’s the 1%. We naturally gravitate toward software with a single purpose because its easier to remember and we know exactly what we’re doing when we’re using it.