I don't know much more than what I put into my post, which is more or less standard industry knowledge.
One more thing I should mention - this isn't a purely IT-driven story. Goldman doesn't simply have better IT than Citi or the Morgans. Citi has had many mergers and acquisitions (e.g., Vikram Pandit came onboard when Citi bought his hedge fund), whereas Goldman is mostly homegrown. Even if Goldman's geniuses ran Citi, they would still never be able to do what Goldman did.
One more thing I should mention - this isn't a purely IT-driven story. Goldman doesn't simply have better IT than Citi or the Morgans. Citi has had many mergers and acquisitions (e.g., Vikram Pandit came onboard when Citi bought his hedge fund), whereas Goldman is mostly homegrown. Even if Goldman's geniuses ran Citi, they would still never be able to do what Goldman did.