In my many years of creating presentations for lectures and conferences, I've always hit a snag when trying to highlight information while giving the presentation. At some points, I've tried to use the crummy tools in PowerPoint that let you sketch a little or highlight something, but often that resulted in me interrupting a presentation and then needing to restart it. Keynote offers a nice build system, which I've used to create objects that are hidden but appear in sequence to identify specific parts on a slide. It's all a little wonky, though.
OmniDazzle from The Omni Group offers a nice alternative that has a lot in common with cursor-finding programs, but includes features that have specific utility in presenting information to an audience, whether using a presentation deck or just showing text you want to pick apart.
OmniDazzle is a mouse-dropping program, if I can be coarse; the application has several methods of leaving traces or producing behavior based on mouse position or dragging. Some of these are the equivalent of Edward Tufte's "chart junk" definition: They don't improve communication and can impair it. (Think about 3D transitions in presentations and 3D pie charts in print, to note two horrible examples.)
But several of OmniDazzle's tracking tools are useful whether presenting or just trying to find the cursor on a giant display, the company's ostensible motivation for developing this application in the first place. The tools generally dim the rest of the screen while highlighting a particular area. Flashlight puts a circular focus around the mouse as it moves about. Focal Point highlights the current window with options to flip between an area in the window and the entire window. Scribble lets you draw in one of four colors on screen. Cutout allows you to draw circles, ellipses, and rectangles additively to highlight parts of the screen. Zoom increases magnification on a selection you make.
I can't speak as highly about Sonar, Waves, or Comic, which are just silly proof-of-concept plug-ins, but Pixie Dust makes me laugh. A little work and it be turned into a great April Fool's Day joke that hides the application and takes over the mouse droppings.
The interface for previewing the tools and configuring their options is just flipping weird and awesome. The top of the window is a series of 3D rectangles with foreshortening and reflection. The current selection is labeled and highlighted in the foreground, parallel to the screen. Make changes to the settings for that tool, and the changes appear immediately in the preview.
The triggers for tools include Key, Button, and Shake. Key allows keystroke assignment, while Button lets you choose a particular mouse button. Shake is a hilarious and useful tool for presentation. "Shake" the mouse, moving it back and forth rapidly, and the tool activates; you set how many shakes are necessary to activate the tool, as well as the deactivation period.
No two tools can be active at once, and you can't rotate among tools from the keyboard. In a future version, I expect you could assign different keystrokes to invoke different tools, or use a command to exchange the active tool.
The software is timer-ware: you can use it for an hour at a time without having purchased a license, but must quit and relaunch the program when the time is up. A $15 license eliminates that restriction.