Where is the boundary to be opened when I use Visifire under the GPL?

Question

Now, my company is developing a web site that needs to show graph charts. I found the Visifire as the most famous one based on ASP.NET. And I also found it is distributed under the dual license.

I know the time of GPL's virus effect is the time of distribution. So almost of server program doesn't need to be opened. But I think Silverlight program is a client application executed on a Web Browser. Before executing the Visifire graph chart, we download the program. I think it satifies the condition of GPL's virus effect. If my thought is not wrong, where is the boundary of the source code to be opened?

Answer 1

You need legal counsel to answer this question correctly. Without seeing your program I cannot make a valid assessment of your particular situation.

In generic terms, the GPL states that if you combine your application with a GPL application, then both have to be licensed as GPL. So, a good rule of thumb is if you have to add a reference to a GPL assembly, then everything in the current solution is most likely GPL. If you break your application into tiers with a service layer that doesn't have a reference to any GPL assemblies then your service layer doesn't have to be GPL.

As an example, I could go out a and write a Silverlight client for Twitter and publish it GPL and that will not "infect" the Twitter service and make it a GPL system. The same is true if you separate your applications into separate solutions for each tier.