Open...and Shut Even as open source has become big business, some of the world's most popular open-source projects remain labors of love for a growing body of developers. Such developers invest years of their lives writing code and fielding complaints from free riders, and they actually seem to like it.

Or love it, in the case of the lead developers at VideoLAN (VLC media player) and Adblock Plus, both of which I interviewed recently in an attempt to better understand the motivation driving the development of these hugely popular, consumer-focused open-source projects.

Both projects have attracted significant interest from venture capitalists, which isn't surprising given that Adblock Plus claims 20 million active users and VLC reaches 80 to 120 million users.

Yet both have largely spurned the moneyed class.

Not content to turn away big-money VC contributions Adblock Plus lead developer Wladimir Palant rejects cash donations of any kind, declaring that: "Money is nowhere near as useful as [contributing translations, testing, reporting bugs, and general evangelism]."

Recently, however, Palant accepted a sponsorship of sorts that allows him to work on the project full-time. But Palant is clear that he was willing to wait for a sponsor/investor who cared about more than money:

I actually had to wait for somebody who is serious about it and wants to help the project succeed, not just make money from it. The other offers were typically about helping distribute other add-ons or advertisement (oh the irony), all of which were rejected without thinking twice.

It's much the same for VLC, as lead developer Jean-Baptiste Kempf told me:

So far, nothing was done [with VCs], because if we ever do something, we need to find a business model that actually adds value for the users. Most business models we've been proposed were linked to shipping toolbars and other crapware while installing VLC. This is not interesting for us.

It's that willingness to emphasize developer and user interests over VC interests that ensures the project continues to command loyalty from both. This is critical because, as Kempf stressed, most of the work is done because it's fun: "A few features are [paid for by sponsors], more than 95 per cent of the work is volunteer work, [done] for...fun."

Fun. Is that enough?

For VLC, it just might be. Kempf estimated that hundreds of man years of development has gone into VLC, much of it done in developers' free time, as none are paid to work on the project full-time.

But probing a little deeper, it's clear that more than fun motivates Kempf:

I've been contributing to VLC [for] five years. I was a student at the French University (École Centrale Paris) where most VideoLAN work was done. When I was doing an internship, I was bored and joined to help the development. It is a great deal of work, especially since it is done during my free time. I still work on it for two main reasons: I learn a lot during my VideoLAN and VLC activities and I think what we are doing is actually helping people around the world.

It is this last thing that strikes me as offering the most vital reason for the significant contributions to VLC, and it also comes through in Palant's decision to invest so much time in Adblock Plus. He told me: "I have the feeling that this work is important. I can help many people and in the long term the web might actually become a better place."