Twitter had a rough go of it today, and the company has now posted a blog entry describing exactly what caused its on-again, off-again ride. In the post, the company's Mazen Rawashdeh describes that the issue first manifested around 9AM PDT, and as mentioned in an earlier tweet was due to a "cascading bug" within the service's infrastructure. True to its name, the bug cascaded across Twitter as a whole, taking down the service worldwide. The company rolled back to a previous version of the service, though it still took several hours for Twitter to come completely back online. Rawashdeh writes that the company has enjoyed its highest uptime ratings in its history over the past six months, and to be fair the service has come impressively far from the days when the fail whale was so common it became a meme unto itself. The company is conducting a review so it can help prevent this type of situation occurring in the future.