[lubos]

Nothing (except for badges/karma which are intangible and cannot be translated to $$).

Once you start offering anything tangible to me, I start thinking about how does it translate to my hourly rate and this is where you will fail.

So much has been written about why Amazon has the best reviews ever without ever paying a cent. Why Wikipedia is the greatest encyclopedia ever with last (and only) paid contributor back in 2005. etc etc...

If you start offering people something in exchange for their contribution, you will fail. Just look at Google Knol.

[moontear]

"So much has been written about why Amazon has the best reviews ever" please do provide some links! I'm very interested.

[lubos]

you can start here (read the comments too for more references):

http://www.codinghorror.com/blog/2007/04/is-amazons-mechanic...

[pmorel]

Does Badge/Karma work with all types of audience?

[lubos]

Not really. Don't think of badges & karma too literally. They are just tools to provide gratification.

It wouldn't be effective for Wikipedia since only the feeling that you are contributing to the most popular encyclopedia in the world gives you enough gratification to do it. Linux contributors don't need badges for the very similar reasons too.

But of course, the smaller you are, more tools and tricks you need to utilize to help users feel gratification for their contribution. This is the key.

[mjdwitt]

I was under the impression that most Linux contributors were actually paid by some other employer who happened to use the Linux kernel in their own products and contributed their patches and drivers back upstream. That said, there are still a large portion who do the same sort of work completely for free.