[mpeg]

Because it's not clearly illegal...

For instance, here's a google search [0] that gives you access to the same pirated material that Popcorn Time does (but with a worse UI)

Does this mean google is an illegal site? Is HN an illegal site? It can get pretty complex.

[0]: https://www.google.com/search?q=yify+jurassic+world+filetype...

[junto]

Out of interest it works using Bittorrent right?

In Germany you won't have problems downloading movies, but uploading them gets you quickly a nasty letter and further abuses escalates to prosecution.

Since Popcorntime is using Bittoerrent, does it just download, or does it upload too?

[mpeg]

Both, like any Bittorrent client. The difference is it uses a library which prioritises certain file chunks so that you can watch it as you download (stream it).