In order for a technology to take off these days, it has to be simple. Twitter, Facebook, iTunes, Spotify – each can be summed up in a sentence or so and readily understood from the very first time you use it.

Tomahawk is more complicated, but if you're a music fan who listens to music on a laptop or desktop – and has friends who do, too – it warrants a try, and possibly a place in your quiver of favorite music apps.

First if not foremost, Tomahawk is a media player along the lines of iTunes or Winamp, which can play the music stored on your computer. The fun starts when you install Tomahawk's content resolvers, which are basically plug-ins that can find music to play in a bunch of other different streaming services, using their search APIs (application programming interfaces) – Spotify, Official.fm, YouTube, Bandcamp, Grooveshark and others.

Whenever you try to play a song, Tomahawk might use any combination of these sources to provide the audio. For playing your own locally stored music, that's a fairly useless feature. You already have the song, so why would you want to play it in Spotify instead? However, Tomahawk gets more useful when you're trying to play stuff you don't already have – for example, a playlist from a Tomahawk-using friend.

"When I want to play a song, or somebody sends me a song, they're not sending me a song – they're sending me the metadata about that song – artist, track, possibly the album," explained Tomahawk open source contributor Jason Herskowitz. "Then, on my side, Tomahawk says, 'OK, out of all the content sources that you have access to, what's the best match?'"

Within the same playlist, Tomahawk might grab one track from your local machine, another from your friend's machine, a third from YouTube and a fourth from Spotify. After all, you don't care where that music lives; you just want to hear it.

Note that Tomahawk can play tracks from your Tomahawk friends' computers, which makes Tomahawk a P2P streaming client with which you can listen to your friends' collections, tap into your work computer's music from your home computer, and so on.

Tomahawk is much easier to use now than it was back when we wrote our lengthy tutorial on how to use it, but it still requires a small degree of technical sophistication. The main hurdle: installing the content resolvers, which are the plug-ins that let Tomahawk hook in to YouTube, Spotify and the rest.

It's easy enough. You can either go to the Tomahawk page and choose the resolvers you want from the list, pictured to the right – or (this is easier) just go to Tomahawk > Preferences > Resolvers and install them from there. (In the case of Grooveshark, Spotify and any other unlimited music subscriptions, you'll need to be a premium subscriber in order for it to work.)

"Local network" lets you play songs from other computers on your own home network, the same way you can in iTunes. "Extended network" lets you tap into your friends' collections on their computers, so that if you don't have a song on a given playlist, it plays from their machine. (They need to be running Tomahawk at the time.)

The latest version of Tomahawk (0.3.3) includes the ability to listen along in real time with your friends and make radio stations that resolve to any sources to which you have access. (The latter uses technology from The Echo Nest, publisher of Evolver.fm.) It also includes nice extras like the ability to choose only high-quality music from YouTube.

Now for the $64 million question.

"How does Tomahawk plan to make money?" asked an audience member at NY MusicTech Meetup.

Herskowitz replied, "We don't."

Audience member: "So, why do you...."

Herskowitz: "Tomahawk is an open source project that we work at out of the goodness of our hearts and a passion to solve this problem: All of the media players that have been around for 10 years were built to solve problems of 10 years ago. We don't need [CD-R] label-makers, we don't need to print CD cases, we don't need to worry about a lot of things that old players like Winamp, which I worked on back in the day, has to worry about.

"The problems that you need to solve today are, you've got silos of music everywhere. I've got my library of music in Exfm, which I love, I've got stuff on Spotify, I've got stuff everywhere else, and I'm forced as the user to bounce between interface to interface to interface, and there's no way on earth that I can listen to a playlist that goes from the Beatles to my cousin's band to my favorite stuff at home to some live recording that I found. This basically solves that problem. It's a very user-centric view."

Indeed. Still, Tomahawk doesn't have it all. For sending music to Apple AirPlay speakers, for instance, you'll need to use AirFoil software (at least until OS X adds native AirPlay support later this year).

As for Android and iPhone versions, Herskowitz said, "not yet."