What I have to say here is in the spirit of learning from what is 'out there'. It is, by now means, meant to be a criticism of any particular project. I have a goal to co-evolve with others a deep understanding of architectures, potentials, and solutions. I have been attempting to build some of the projects.
AKSW OpenQA: building in Eclipse, found some jars missing, and one unresolvable import:
javax.servlet.annotation.WebServlet That bug was fixed by upgrading the servlet-api jar. So, now, we have OpenQA ready to test.
AKSW QA: building with maven: stale maven repos, issue of two separate builds in one project, each requiring the other.
Machine_Reading (internally, kgraph). Ib uses something from OAQA, but the pom is stale. It seems to need the OAQA Graph DB, but that project appears to have matured; the project cannot be built; it also includes hard-wired locations on a particular hard disk. My guess is that this was a student project, abandoned after putting it at GitHub.
DeepQA: built in Eclipse. Builds with no compilation errors, but Eclipse insists "Target runtime Apache v 7.0 is not defined". From what I can tell, that's because I do not have a Server environment in this Eclipse. So, it builds. At the moment, it's not clear what to do with it; not sure how it boots data, where it stores it, etc. Still a lot to learn.
On the lighter side: YodaQA came up. My experiments with it are documented in a wiki page at the YodaQA repo.
I built a copy of Netention. Had it online running fine. Of course, it's not really a question answering platform, but it is a powerful user interface, capable of supporting such projects.
Up next will be to build Watsonsim, and to attempt to get DeepQa and OpenQA running.