This addon is no longer updated and support is not guaranteed
The addon looks something like this:
This addon adds this button to the lower left corner to all sites except admin area, if you click on it, this menu will open.
What Is Arc.io?
Arc (https://arc.io/) offers websites a new currency to make money: unused device bandwidth from users. ... We rent this fast, people-powered CDN to you and other websites, and you get paid for the bandwidth your users share while they browse your site.