This is a Minecraft server plugin that add player-created portals that are "linked" together with a specific item, that can be treated like any other item. Players can, for example, create a portal and give out links to that portal so that any player on the server can portal through to it. It also allows portals to link in any fashion, so that entering portal A leads to portal B, which leads to portal C, and in any other fashion.
Tutorial Video: https://www.youtube.com/watch?v=85G884JN8pA
Earlier Demo: https://www.youtube.com/watch?v=y6kl12JFe-Q
I forgot these, but I'll figure them out and update them later.