Yesterday, Yahoo announced that COO Henrique de Castro was leaving the company.

CEO Marissa Mayer made it clear in an internal memo she was firing de Castro, writing, "I made the difficult decision that our COO, Henrique de Castro, should leave the company."

De Castro was Mayer's first big hire. She thought he was responsible for the growth of Google's display business, and wanted him to rebuild the display ad business for Yahoo. She gave him a big, $60 million pay day. He earned more last year than Mayer.

After less than a year on the job though, Mayer and De Castro were reportedly at odds. De Castro was reportedly grating on other Yahoo executives, too.

The even bigger problem is that de Castro was reportedly struggling to turn Yahoo's ad business around. At Google, he was partly responsible for the rise of the display ad business, but as a source told us when he was hired, Google had YouTube, DoubleClick, and a formidable staff of product managers and engineers.

After news broke that de Castro was out, an industry executive and a former Googler sent us the following video of de Castro presenting at last year's IAB Leadership Conference. IAB is the trade group that represents online advertising.

Our source said the video, "says it ALL." His presentation, which was in February of last year, has de Castro sort of spinning his wheels as he tries to lay out his vision for Yahoo. Our source said, "It's a disaster. The worst executive presentation of all time in my opinion, and not just because of the language barrier. People joke about how terrible it is."

This was early in his tenure at Yahoo, but it set the stage for de Castro's struggles to come.