NEW YORK -- Struggling online deals pioneer Groupon has ousted its quirky founder and CEO Andrew Mason amid worries that people are tiring of the myriad restaurant, spa and Botox deals that Groupon built its business on.Shares jumped after Thursday's announcement, which had been expected for months. Executive Chairman Eric Lefkofsky and Vice Chairman Ted Leonsis were appointed to the office of the chief executive while a replacement is found."I've decided that I'd like to spend more time with my family. Just kidding -- I was fired today," Mason, 32, wrote in a memo to staff."If you're wondering why, you haven't been paying attention."He referred to controversial metrics used in its regulatory filings ahead of Groupon's November 2011 initial public offering, as well as "two quarters of missing our own expectations and a stock price that's hovering around one quarter of our listing price.""The events of the last year and a half speak for themselves," he wrote. "As CEO, I am accountable."The announcement came one day after Groupon reported a bigger-than-expected loss and gave a weak revenue outlook for the current quarter. The guidance had fueled investor worry -- which started even before Groupon's IPO -- that people are suffering from fatigue over the emails flooding subscribers' inboxes. There were also worries that efforts to broaden into an e-commerce powerhouse haven't paid off.His ouster has been "fairly widely expected," Gartner analyst Michael Gartenberg said."The question is whether this as a business model can last -- it's easy to replicate and under a lot of pressure""There was always a sense that Groupon had a lot of good ideas but no real focus," Benchmark Capital analyst Daniel Kurnos said.