The acquisition of Crashlytics, a crash-reporting tool for mobile app developers, adds to the growing nest-egg Twitter is building. The deal allows Twitter to fully integrate Crashlytics’ technology while still making it available to current and new customers. Crashlytics raised a reported $6 million in venture capital prior to the acquisition. The company has a hefty client list, including Twitter, Vine, Yelp, Kayak, Wal-Mart, Groupon, Waze and TaskRabbit. In related news, the Twittersphere remains abuzz with talk of Twitter planning an IPO later in the year. Exiting investors include Baseline Ventures, CommonAngels and Flybridge Capital Partners.