it is just an alternative to home servers and consumes approx 5 watts. There are other uses for TonidoPlug - not limited to media streaming
It's a packaged sheevaplug http://www.marvell.com/products/embedded_processors/develope...
You can do the same thing using fuppes, an updated version of uShare. Fuppes also supports transcoding, uses a sqlite backend and can rescan watch folders to rebuild the database pretty quickly (either from cli or web interface, without restarting). I use it to stream to an xbox360 and it works perfectly. Haven't tried transcoding though since all my video is compatible.