In a statement on its blog today, Bitly has announced that CEO Peter Stern has stepped down as CEO. The reason is that Stern is to “pursue other interests”; further details aren’t known at this time. The NYC-based company has raised $28.5 million to date, with the last round being a monster $15 million one by O’Reilly, RRE and Khosla last July. Stern was the CEO for a little over a year, after founding Zenbe, a mobile collaboration company with mail, shareflow and list services. Bitly was in the driver’s seat for link-tracking analytics with its popular short-URL service, and the definition of a hot startup. Once the social web took off, marketers and advertisers everywhere clamored for ways to see how their campaigns were doing in real-time. Bitly has since cooled off since services like Twitter have started handling their own short URLs. In January, the company announced a new set of social-tracking APIs for developers in the hopes that its service would be included in other hot metric products. Regardless, this definitely seems like an odd time for a CEO to get bored and move on, so we’re digging for more details: Bitly is announcing today that Peter Stern has resigned to pursue other interests. “Peter has been a key leader and contributor to the Company,” said Bitly Board member Sam Mandel. “In particular he has been instrumental in transforming Bitly into a successful business while growing its unparalleled data set. We are very happy that he will remain a shareholder and supporter.” We’ve reached out to Bitly for more information and will update as soon as we hear back. Sources tell us that the overall health and direction of the company is in question, which might explain why the short blog post announcement had a quote from a board member via betaworks. If you’ve heard anything, do reach out to us on the tip line. Developing…