Some screencasts are carefully produced works designed to educate, entertain, or influence an audience. But the confluence of broadband, blogging, and ubiquitously multimedia-capable computers has also opened the door to ad hoc uses of the medium. For users of software products interested in explaining those products to other users, showing and telling—that is, screen-recording and narrating—can be both easier and more effective than written descriptions accompanied by static screen shots. An ad hoc screencast can also be the best way for a user to communicate with a developer about a hard-to-reproduce bug or a user-interface wrinkle.
Here are some of the ways screencasts are used.
Tutorial: A screencast that demonstrates how to use an application or service. The screencasts on my LibraryLookup page are examples of tutorials. One of the most dramatic examples of this genre is called Cracking WEP in 10 minutes. To a thumping electronic beat, it shows you how to use kismet to locate a victim, aireplay to generate the requisite hundreds of thousands of WEP initialization vectors, aerodump to save the traffic to a file, and aircrack to analyze the file and recover the WEP key. It's a stunning contribution to the literature of wireless security.
Short how-to: Examples include this 90-second short on Linky, a Mozilla/Firefox extension, and another shortie on Windows' hidden desktop search feature. For screencasts as brief as these, editing is optional because you can get a usable result in a single take. That means that almost anybody can create one, blog it, and thus make it discoverable by search, tagging, and word-of-mouth referral.
Conversational demo: My first effort here was a demo of JotSpot, the "application Wiki," in which Joe Kraus drives the demo and I ask questions. A more recent example is this co-narrated demonstration of Zend Platform. As software grows ever more complex and dependent on elaborate substrates—especially in the enterprise category—I expect that this genre will be increasingly useful as a way for developers, reviewers, and users to reach a shared understanding of the software.
Feature story: My first foray into this genre was Aunt Tillie's OS X Adventure, in which I respond to a pair of Eric Raymond essays [1, 2] on the horror of Linux's printer support. Eric had suggested that Mac programmers wouldn't make the same mistakes. But what I found on OS X, and documented in the screencast, was an almost equally bad experience.
Good old-fashioned software review: If you're reviewing a software product, for example the latest version of Photoshop, why wouldn't you do it as a screencast? That's just what David Pogue did.
I put very little consideration into making that narrated demo. I had posted something about XSLT and said it was easier than advertised. In a weblog comment, someone asked for evidence to back up my assertion. I offered to make a recording, he took me up on the offer, and I spent 15 minutes with no post-production to respond to him. [Zope Dispatches]
Capturing a screencast needn't be much more complicated that capturing static screenshots. Whether you're showing a friend how to use an application, or showing a developer what's wrong with one, the ability to make and share screencasts easily and naturally promises to revolutionize the flow of information supporting the use and development of software.
Animated whiteboard: Troy Stein, product manager for Camtasia Studio, made this screencast for the soccer team he coaches. It's particularly well suited to the Tablet PC, but you could use sketching software on any platform to achieve a similar effect.
Screencast-enhanced video: Although most of my screencasts have focused mainly on software action, with bits of live video sometimes spliced in, my screencasts about a flood and a pumpkin festival reverse the emphasis. They're mostly video, with bits of screen animation interspersed to contextualize the scenes. You can see the same mix of ingredients in this David Pogue video. His review of a hard-disk-based camcorder is mainly video, with just one short screencast to illustrate the use of the camera's software.
Concept screencast: The ACLU's digital identity nightmare is a screencast about software that doesn't exist, but could: an application for a pizza store order-taker that violates the customer's privacy in a dozen different ways. It's a powerful polemic that's influenced a lot of people. I've argued that architects of more humane digital identity futures ought to be using the same medium to communicate their alternative visions. In general, concept screencasts can be a great way to explore alternative software-based realities.