The Mentorguru chose 18 mentoring sites and/or blogs on his list regarding mentoring and is asking for folks to help define the discussion /selection. I wish I'd made his list but, given that Google produces about 11,800,000 results
The sites I reference weekly are not necessarily about mentoring but often inform my ideas around which I either mentor or am mentored:
http://creativityatwork.com/ Exploring "creative leadership capabilities"
http://blogs.hbr.org/ Harvard Business Review eclectic collection of topics
http://www.scienceofpeople.org/ Creating "bite-sized" research about people–relationships, human behavior and personal development"
http://cci.mit.edu/ Asking how people & computers can be connected to collectively be more intelligent as a group than as individual contributors
http://theinvisiblementor.com/ A thoughtful collection of interviews and posts around mentoring