The interesting areas of overlap IMO cover social learning, communities of practice and peer to peer learning.
There is a close relationship between e-learning and KM as both domains seek to increase awareness, increment competencies, stimulate innovation and introduce new ideas.
Both areas have tended to focus way too much on the technologies and to move slowly on the cultural issues, both need to find ways to deal with fundamentals such as shared meaning, identity, delivering useful context, discovery and emergence via dialog and self-motivation.
KM and e-learning share this duality around personal vs. group processes, how to find the balance and where to focus attention and energies. In KM, this is articulated as personal knowledge management (PKM) and in e-learning the mantra is self-directed or paced learning (SDL). If you share the view that knowledge is a social construct and all learning requires validation and feedback – you may question the utility of PKM & SDL directions taken to the extreme.
These areas share many practices and tools, think of AARs (after action reviews), lessons learned, case studies, capture & sharing of experience via stories and pattern languages, mentoring. Web conferencing, IM, blogging, Wiki, groupware, best practice repositories, FAQs are examples of technologies that cross the boundaries.