Miro described itself as Open-source, non-profit video player and podcast client. It's actually somewhat a swiss-knife for videos if you are using video sharing services (like youtube or dailymotion), following podcasts and downloading videos via bittorrent.
Miro lets you do everything in one place. You can directly search for a video, download it and see it locally. Then you can organize your videos whatever it comes from and remove them when you want. To me, it's sound like the equivalent of songbird for videos.

Miro is also known for it's "Adopt a line" campaign which consist of paying 4$ per month to adopt a line of code and support the project. An innovative idea which seems to work.

So, bug 131527 is now fixed and Miro is known as media-video/miro in Gentoo's tree.
Try it and report bugs !