Are there any scripts to offer blog services?

[tomld2]

I would like to embed a free blogger service as a small portion within my larger site. I am wondering if there are any blogging scripts that allow webmasters to run their own blogging services? I know there are several open source bloggers such as wordpress, but under the GNU license they require revealing source code of any modifications I would make, thus not interesting me in using an open source script.

So does anyone know of a paid script that allows webmasters to run a blog service?

Thanks
Tom

[pompousjohn]

I think you only have to reveal the source code if you distribute the resulting modification.

Lots of people are using open-source software and they don't have to reveal their stuff to anybody. It's only if you distribute your own version afterwards.