"A software product description is nothing without screenshots.
They are the most-clicked links on almost every free software
page--much more than 'Download.' Screenshots carry information
about the software's appearance, maturity, user interface, user
friendliness, and feature set in a much more immediate way than
paragraphs of text description. You can't show some software
characteristics with still images, however. That's why, in recent
months, the screencast has seen growing popularity. And when you
need to creating screencasts, Istanbul and Wink make the process
easy for Linux users.
"Just as a screenshot is a picture of a user's screen, a
screencast is essentially a movie of what a user sees on his
monitor. And if a picture is worth a thousand words, a movie is
worth a thousand pictures..."