If you spend much of your day shuffling files to and fro on your Mac, let Dropshelf lend a hand. This Mac app -- currently discounted at $1.99 -- provides temporary waystations for the files you drag and drop during the workday. The app provides little slide-out shelves at the edges of your screen where you can stash files momentarily, helping keep your desktop uncluttered and your open windows to a minimum. The app lets you stash a variety of things on its shelves, such as files, images, clipboard items, URLs, and even colors from a color picker.
With Dropshelf installed, you can drag a file to the edge of your display and the app will helpfully slide out a small, striped shelf to hold a copy of the file. To be clear: your file stays in its original location, but a copy of it sits conveniently on your screen's edge. You can then drag a file from a Dropshelf shelf to another location -- say, to the compose window of an email to attach it. Alternatively, you can click on the file name in Dropshelf and you'll see three options: Open, Copy, or Show in Finder.
In addition, you can drag a file to an existing shelf. A shelf can hold multiple files -- up to 64 -- and the shelves are accessible across multiple desktops (if you have set up such an arrangement using Spaces). In contrast to files and images, shelves can hold only one URL or text clipping at a time.
Be sure to drag files straight horizontally or vertically to activate Dropshelf at the edge of your screen; if you come in at an angle, you might accidentally drag a file to another desktop screen instead of to a shelf. If you want to avoid triggering a shelf when dragging a file to the edge of the screen, hold down the Shift button.
Dropshelf places a small icon in the menu bar. From here, you can create a new empty shelf or, more conveniently, create a new shelf with whatever it is you have copied to your clipboard. The latter is particularly helpful, I found, when copying URLs to Dropshelf. From the menu bar menu, you can also reopen the last shelf that you closed.
From the menu bar icon, you can also access the app's preferences, where on the Behavior tab you can select on which edges Dropshelf shelves can appear. By default, they are active on the two edges where your menu bar and Dock are not located. Also on this tab, you can keep the inactive shelves from sliding closed when inactive, though even when they're minimized, you can still easily access them by mousing to their visible edge. On the General tab, you can tweak Dropshelf's appearance, choosing from three striped patterns for the background of the shelves.