This add-on allows users of Firefox Sync to remotely open tabs on other Sync-connected devices.
To use this add-on, you must have Firefox Sync configured with two or more machines. Then, once Sync is initialized on Firefox startup, you should be able to right click on any link or anywhere inside a page and see an option to send it to another device. Just click the device you want to send to and the next time that device synchronizes with Firefox Sync, the link should open in a new tab!
This feature will eventually make its way into Firefox/Firefox Sync. Until it is officially ready, you can use this add-on. Once the feature is officially available in Firefox Sync, this add-on will automatically uninstall itself.