This addon needs a lot of work as I love the idea, and it seems to be the only alternative to Firefox Sync. Why use this this instead? Because in Firefox's Sync, right-clicking a tab and selecting Send Tab To Device won't show all of the computers and browsers that are logged in, but rather it seems to limit the number of computers and browsers shown in the popup submenu's list. Due to the limited number of computers/browsers shown, if you have more than a few signed in, you might not be able to see and select the exact browser you want to send tabs to. That's why I tried this addon.

I had hoped it would solve that problem, but instead I couldn't get the signup to work here either. The signup in the drop-down box of the Share Tab add-on simply ignored the fact I had entered email, user and password and reverted right back to where I had started. Bummer :-(

I would be willing to assist with the development of this add-on if I could.