difference between open source and ...
 

Well, I wanted to get some opinions on this. What makes a project open source? Just that it has some sources released? is it enough? does it have to be free? or have one of those "OSI" licenses?

If it's under an OSI license, it's open source as they define it (which tends to be the commonly accepted form). The range of licenses they consider open-source, however, is quite wide.

There are many different kinds of "open source" licenses. That does not mean that they are free, as in beer, but that they are free, as in freedom to modify the source code. Whether or not you can redistribute this modified source code, or charge for use of the modified source code, depends on the specific license.

Most of us aren't attorneys. Nevertheless, most of us can understand the terms of a license, if we but read it and apply a modicum of thought. Despite that presumed understanding, if one is concerned about repercussions because of distributing and charging for derived code, one would be wise to consult an attorney.

Generally speaking I would say that releasing a little source doesn't make your project open source. You need to release all of it and not restrict redistribution. I haven't read all the various licenses out there but I think these two points are the essence of it.

http://en.wikipedia.org/wiki/Open_source

More than you will ever want to know.