Confused?

[Uphoreka]

What does a following message mean?

You can sell it but it will have to be open source and remain under the license of the GNU General Public License.

 

[golfbunny]

In what context did you receive this message?

Open Source - a software for which the source code is readily and freely available.

Details about the GNU General Public License are available here.

 

[Deleted member 4320]

Depends what context you got the message in, but basically it is saying that as long as it remains under that license you can exchange/sell it etc to anyone, however if it's under that license that means anyone can use it for free. Zane posted some information about it, that should tell you more.