"But as Twitter has grown in popularity and evolved into a real-time news feed and communication tool for many of its 140 million active users, the demand for a way to reach back in time and trawl through the thousands of messages they have posted to the site has become high enough that Twitter executives decided to devote some of its engineers to building a solution. Mr. Costolo said that while the company was developing a way to let users dig through their own backlogs of past posts, he did not anticipate that a similar tool would be released to let users dig through all of Twitter’s trove of posts anytime soon. “It’s two different search problems,” he said. “It’s a different way of architecting search, going through all tweets of all time. You can’t just put three engineers on it.”" - × × ×