This one is a tad bit late since I lost it in my bookmarks. In any case, the article describes the “killer” of OS software such as Blender and the GIMP. However, the title and use of the word “killer” are misleading.

When I think of a killer application, I think of software that is unavailable on any other platform. Software that is not duplicated on other platforms and if it is the duplication is nothing close to the original. Therefore I see these as alternative applications and not killer applications. All really wonderful though.