If we in the learning-and-performance field are serious about on-the-job learning (a much better term than "informal learning"), we need to be serious about how managers in organizations do their work, and specifically about how they guide learning on the job (and incidentally how they use formal training initiatives to enable and improve on-the-job learning).
Recently, a group of leading management thinkers got together to re-imagine management.
Here is a brief blog post on their thinking. It is well worth some reflection.