It's a browser extension that allows you to circumvent many regional content messages and watch videos that are often blocked for people outside of the US or UK.
You don't need to subscribe to anything to use the extension, but content that is behind a paywall will still have to be paid for if you want to watch it.
Orphan black seems to be paid only as far as I can tell from TV.com. I watched some anime on Hulu, but the quality is pretty bad. Better off torrenting. Don't know if quality improves when you start paying... but seems like illegal downloads provide a better service yet again.
It's nice for watching videos on specific websites though, often tv show websites.