In paper-based offices, a common way of organizing information on a large scale was a cork board. The soft cork allowed documents to be attached to it using short pins with easily gripped heads that let you move them around. It was common to have a large map or enlarged paper photo print on the board, and use pushpins to attach other documents to it, or pin pieces of string to indicate connections. Cork boards are often still in use as community property, allowing people to pin advertisements, posters, and reminders on them easily and reversibly.
Blackboards (which used chalk) and whiteboards (erasable pens) are modern version of these, but tend to use magnets, if things can be attached to them at all.
The concept of sticking something to your working surface, however, has remained in the form of the pin. You “pin” items to your to-do list, “pin” places on virtual maps, and of course there is an entire pin-based social network. All these uses are direct extensions of the original idea, though the style of pin, from thumbtack to round-topped pushpin, or even a simple ball-headed needle, differs. Sticky notes are another version of the same thing, but tend to focus on saving text, rather than things.