Sidebar: How Groove?s swarming technology works

Computerworld - One of the most highly developed commercial offerings in the swarming market is Groove software from Groove Networks. This desktop collaboration software uses a peer-to-peer, decentralized architecture, meaning the application resides on users' PCs, not on a central server.
It sends encrypted XML documents and messages between PCs via the Internet. If a user is behind a firewall, the software pushes the encrypted XML messages to a relay server, essentially a store-and-forward router with a disk, where the XML packet is wrapped in HTTP and then sent to the recipient's PC by tunneling through the firewall port that's open for Internet traffic.
If a message is sent to someone who's off-line, the encrypted message is stored at the relay server. When the user comes back online, the message is sent automatically.
Groove uses military-grade 192-bit encryption, so all information stored on users' PCs and sent across the Internet is secure.
Because Groove is client software, not Web-based, all the tools and materials reside on the PC, so people can work off-line as well as online. When an off-line user reconnects to the Internet, the software automatically synchronizes, so everyone working in the shared space has up-to-date information.
Groove costs $149 per client, with additional charges if the vendor hosts relay or management servers.