During a visit to Australia this week, Flickr founder and former Yahoo staffer Stewart Butterfield criticised the search giant for its lack of an innovative culture compared to rival Google.
"I felt like the biggest problem while I was there [was] that management was oriented a little bit too much towards the quarterly results," said Butterfield in an interview with ZDNet.co.uk's sister site, ZDNet.com.au, on Monday.
The executive and his wife, co-Flickr founder Caterina Fake, left Yahoo in July as part of a wave of management departures, more than three years after Yahoo bought the photo-sharing site in March 2005, for an amount believed to be at least in the millions.
"If the entire focus of the company is produce a certain amount of operating free cash flow or a certain amount of capital expenditure... it isn't hard for other people to out-manoeuvre you, when they're not so concerned about those things," Butterfield said.
Butterfield said he saw Google as a more innovative company.
"I am sure the management at Google, despite their outward proclamations, are every bit as concerned about those numbers, but they are taking bigger strategic risks, and other web start-ups are as well," he said.
Butterfield also spoke out about Microsoft's attempt to buy Yahoo, the failure of which has resulted in diminished confidence in Yahoo chief executive Jerry Yang and a management exodus at the search firm.
"It was not so great," he said. "Once the ball was rolling I would have rather seen the acquisition happen. I think a lot of damage was done to Yahoo. Not only from a company perspective, but from a leadership and morale perspective."
However, Butterfield denied that he left Yahoo because of the culture at Yahoo or the failed Microsoft merger.
"I didn't leave because of Microsoft stuff," he said. "We had a three-year commitment, and I stayed a little bit longer than the original agreement."
When asked about his unusual "tin-smithing" resignation letter, Butterfield said it had no deeper meaning.
"I figured if I had to write an email that said my last day will be 12 July... then I would make it a little more interesting for the people that have to read it," he said.
Butterfield was in Australia to attend the X|Media Lab in Melbourne.