Subject: Re: Open Source stock portal app Question
From: Matthew Flaschen <>
Date: Sun, 07 Sep 2008 17:25:38 -0400

Daniil Kulchenko wrote:
> I plan to have the portal version as one of my websites, so that people can
> come register and try it out, so my question is: *how can I prevent people
> from* taking the portal code, and making their own stock portals,* then
> charging people to use it?*

You can't if you want it to be Open Source.  /However/, what you can do
is require that the portal operator release their version of the code
under your license.  Then, if you like one of their innovations, you can
add it to your gratis version.

> Is licensing the portal code under the GPL
> enough, or do I need to do something else?

You should use a strong copyleft license that closes the web services
"loophole".  Possibilities include GNU Affero GPL version 3
( and Open Software License

> Basically, I don't want (for
> example) Yahoo taking my code, and making a product out of it without my
> permission.

They'll still be able to use your code, but they'll have to publish
their modifications.  In practice, many portal/SaaS companies are
unwilling to deal with such licenses.  Google for instance says "The
Affero GPL is out there. That's great for the people who use it. It's
just not for us."
 They might in the future, but they will have to play by Affero's rules.

Matt Flaschen