Excellent point. The defining characteristic is here escaping into heroic fantasy. LOTR, Star Wars, Dragonlance Chronicles (in my youth), superhero comics. What does that suggest? A person fantasizing about superpowers does feel disempowered, don't you think?

Yes, the overlap is an issue, nerds don't fully self-identify as a group, the Linux guy will not high-five the anime guy saying "we are bros". It is not really a clearly defined one group. And I am thinking of the second guy.

However nerds who suffer are clearer. See: http://www.reddit.com/r/justneckbeardthings/

Focus on the suffering subgroup and you get it clearer.