NextDesk was an application to easily share files (now superceded by the likes of DropBox) between one computer and another. You'd drag a file to the edge of the screen, where a pop-out bar would appear. Dropping the file onto the bar would send it to the computer that the bar was currently 'connected' to, at which point the file would pop onto that computer's desktop.)
A feature of NextDesk was that it would send files directly from computer to computer if they were both on the same network (or if the destination was contactable directly over the internet); if the computers were both behind firewalls then they would transfer the files via the NextDesk website. Files would be kept for up to 3 days, which meant that you could send a file to a computer that wasn't currently switched on. The destination computer would then pick up the file next time NextDesk was run.
The application was written in Java Swing, using a Substance Look & Feel. It was launched via Java Web Start, and featured strong public-private key encryption so that only the authorised recipient could read the files being sent.