Vgetty turns your voice modem into an answering machine. It adds voice capabilities to mgetty. This means, that you can handle data, fax and voice calls on one telephone line.
Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems, each with its own display, without special hardware. It's intended for users with multiple computers on their desk since each system uses its own monitor(s).
Put simply, Puppet is a system for automating system administration tasks. To learn more, read our big picture overview of Puppet, or take a deeper look at what Puppet can do with the Puppet Introduction. There's also an about Puppet page which gives the highlights of Puppet's functionality.