Fon has been around for awhile. Which is to say, three months. The Spain-based brainchild of Martin Varsavsky, it's a global community of people who share WiFi connections. Also a business. And it's about to get a lot bigger, because Google, Skype and Sequoia Capital have just invested $21.7 million in it. And if you're a "Linus", a "Bill", or even an "Alien", Martin explains, you get to benefit too. Or that's the idea, anyway.

Here's how Fon works.

At the Fon site, you download software that you install on your FON compatible WiFi routher. Namely, a generic Linksys WRT54G/GS/GL (versions 1x to 4x), which are the ones with Linux inside. You can get one through Fon's store for twenty-five dollars or euros. This is, obviously, below cost.

The software you download is based on open source code developed by Sebastian Gostchall (Brainslayer).

Now you can be a fonero (this being Spanish, I imagine the accent is on the second syllable). Foneros come in three breeds: "Linus", "Bill" and "Alien". A Linus gets to use any Fon hotspot, anywhere, for free. A "Bill" gets a cut of whatever Fon charges for using the network, but does not get to roam free. An alien is a customer, and is neither a Linus or a Bill. The rates will be low, but not free. Affordable, basically. Even if you're in the undeveloped world. According to the Fon FAQ, the system is now in beta, and only Linuses (Lini?) are operative.

Now comes the usual question. (You know it, let's recite together...) What's the business model? The short answer is, do well by doing good.

David Weinberger, a member of the Fon advisory board, explains:

The aim is to provide enough incentives, and make it easy enough technically, that thousands of people will start providing Fon hotspots. Bottom up we can have a global network, usable for free by those who choose to share access for free and for an affordable fee by others.

If you know anything about Martin, you know that, having made a bunch of money as an entrepreneur, his heart and hands are all about making the world better. That's the motivation behind Fon. Fon is especially interested in helping to grow wifi in poorer parts of the world.

But Fon has dreams even beyond this. It can be a platform for innovative community development. There are some really really interesting ideas in the works. Say no more.

Martin Varsavsky explains more, adding details about his new funding and how it will be put to use:

Ours is a people's network. But for FON to succeed we need tremendous magnifying power for our message.

So I sought the ultimate alliances in the industry, and aimed high, very high. And today I have a great announcement to make: FON can now count Google , Skype, Sequoia Capital, and Index Ventures as investors and backers. They’ve joined us to help advance the FON movement, leading a group that has put 18 million Euros into FON and also committed to give us a strategic boost that should help us make this great idea into a great platform for everyone who wants a faster, cheaper and more secure wireless Internet. We’ll invest this money in R&D so we can make it quicker and easier to become a FONERO and so that we can expand the number of things you can do with your FON service. Our goal, after all, isn’t just to share bandwidth. It’s to use the power of people to people networks to create a global wireless network. What makes each of these firms great backers for us is that deep in their DNA is the idea of brand-new business models, tons of innovation and a commitment to making the digital world easier and cheaper. We feel the same way. So while we’re excited about (and responsible for!) their investment, we’re even more pleased to have their support. Also I am pleased to announced today that we have obtained the support of two significant ISPs for FON. In America Speakeasy has said that they welcome FON and in Europe, Glocalnet and FON have signed an agreement so Glocalnet sells its services FON ready and the Swedish foneros will soon be able move around Stockholm and other cities with their WiFi enabled gadgets. FON shares revenues with ISPs making it attractive for them to join the FON movement.

Word is spreading fast. Dig into posts by Om Malik, Gizmodo, Skype, Robert Scoble, Ethan Zuckerman, Wendy Seltzer (I'm somewhat of a techie -- I built my own MythTV instead of buying a TiVo), David Isenberg, Rebecca MacKinnon (I'm sick and tired of being fleeced to pay for wifi roaming when I travel), Alec Saunders (This is a pure long-tail play) and many more.

While Martin reports passing 3,000 foneros, the network isn't what you'd call dense, yet. A search for sites near 94707 (Berkeley) yield twenty hotspots spread from Spokane to La Jolla.

And there are skeptics. Glenn Fleishman perhaps chief among them.

So, any of ya'll foneros yet? Interested? Whaddaya think, so far?