Swarm is a reactive data sync library and middleware. Swarm synchronizes your app’s model automatically, in real time.
#sync
ChronoSync
“Perform File and Folder Synchronizations and Backups Like Clockwork”
Echodio
“Seamless iTunes Sync”. Drag and drop iTunes sync! Just drop your tracks into the Echodio playlist to synchronize tracks, tags and ratings across all your iTunes libraries.
Nokia iSync
Nokia page with details on how to sync Nokia phones via Apple’s iSync app on Macs.
Soocial
“Soocial provides a one address book solution to contact management. No matter where you add or change a contact, it will be changed in your other connected devices or web applications.”
Spanning Sync
“Synchronize Google Calendar and Apple iCal. Share calendars between multiple Macs. Share calendars with your coworkers, family, and friends. And while you’re at it, connect Google Calendar to your iPhone, iPod, and other devices.”