IBM's Watson beat two Jeopardy champs in answering questions this week. 

Does this mean that soon computers will be able to replace people in answering questions? For us as workplace learning-and-performance professionals, does this mean we'll be doing less training of people, and more training of machines?

Probably depends on lots of things as to how soon this happens. For example, folks doing technical support probably won't be replaced as soon if the systems/equipment on which they are providing support are updated regularly or modified substantially.

Anyway, this will affect our field—indeed it is already affecting our field to some extent as computers already provide support for folks who are answering questions—but when this reaches a tipping point we'll just have to wait and see.