More or less. It's a sort of network services browser system. If you have an Apple wireless router and connect a printer and/or USB hard drive to it, bonjour finds those services and makes them available. I'm not sure how well integrated the Windows version of bonjour is, but in Mac OS, shared printers automatically show up in the print dialog box, and devices with shared drives or folders automatically show up on finder window sidebars (finder = windows explorer, functionally speaking). It just makes connecting to shared services easier. iChat (Apple's IM program) also uses bonjour to find users on the local network so you don't need an external server to text, video chat or whatever. Really, bonjour's integration is a big part of it's usefulness IMO.They're trying to install Bonjour for Windows on your computer, which is some sort of network software sharing software