[dfgonzalez]

I'm reading the definition of Sybil attack... but I do not understand how multiple accounts per user could damage the platform. Do you mind to extend a little your point?

Def: http://en.wikipedia.org/wiki/Sybil_attack

[nbpoole]

Something like this, I assume: http://www.bitcoinminer.com/post/5328668205/deepbit-50-perce...

[petar]

One attack that was discussed by an economist (in an article I saw on HN) was an attack based on inserting multiple malicious bank servers.