Sometimes when I’m building a bug report for somebody, I’ll make a movie of the application misbehaving. A picture is a thousand words, so a movie is at least 15,000 words a second.
For instance, I saw some strange behavior in Mars Edit’s preview panel with a <pre> block. I could spend a chunk of time describing the behavior, and even then would probably omit some important piece of evidence. Instead, I sent This Movie on to the Red Sweater Empire. DCJ asked me to try some stuff, we narrowed it down to line break conversion, and I found a work-around by putting in a space character in the <pre> block.
Similarly, we have an internal tool at the GOOG which I had difficulty getting working. I made a quick movie of it not working, sent it on to the developer, and he said “huh. you’re doing everything right. Lemme go look for the problem.” Sure saved a lot of back and forth, and also saved a lot of wondering “Is this a PEBKAC problem?” (I’m the first to admit I do stupid stuff.)
Naturally, include a link to the movie in any bug report. Sending someone ten megabytes in an email without prior warning could be interpreted as rude.
There are a number of screenShotMovieMakers. I’ve used SnapzPro for years, and have certainly gotten my money’s worth.