After shutting down yesterday for nearly an hour, Twitter has spoken up about what caused the social network to completely fail. In a message on the company's service blog, Mazen Rawashdeh, Twitter's vice president of engineering, apologized to users and explained that the crash was caused by what he called a "infrastructural double-whammy." 

Data centers are designed to be redundant: when one system fails, as everything does at one time or another, a parallel system takes over," said Rawashdeh. "What was noteworthy about today's outage was the coincidental failure of two parallel systems at nearly the same time." 

To make sure this doesn't happen again, especially during the Olympic Games, Rawashdeh said Twitter is "investing aggressively in our systems to avoid this situation in the future."

[via MNN]