This past Monday, Adobe launched its AIR software, which aims to merge the sometimes-disparate worlds of the Internet and a user's PC. You might think of AIR as a much more sophisticated and versatile PointCast, the mid-90s screensaver that used push technology to deliver news and stock quotes to a user's desktop. It's not a perfect comparison—AIR is platform and not an application—but it's a good starting point for understanding the concept.