Quite the day today turned out to be in the world of mobile industry executives. First Samsung Mobile lost their CTO, then HP played musical executives with the man who kinda, sorta brought Palm back from the dead.

Omar Khan, known in the industry as a friend of Google’s little green robots, left his post as Chief Technical Officer at Samsung Mobile to head up Citigroup’s global mobile initiatives, according to an email posted at TheDroidGuy. I actually had the chance to sit down for an extended one-on-one with Omar just after he took the Samsung job two and a half years or so back, landing in Sammy’s Dallas offices after a tenure at Motorola. At the time I was impressed by Khan’s passion and intelligence, and in the time since he basically ushered Samsung Mobile into the Android age. Khan was responsible for the Galaxy brand of Android phones and tablets, and quickly became a fixture at Samsung Mobile product launches. Folks in the biz generally considered Omar to be media friendly and one of Samsung’s biggest Android supporters, which may or may not be of note given the recent rumors that Samsung has been in talks with HP to license the webOS mobile operating system for use on its devices. At any rate, it’s a loss for Samsung Mobile who, incidentally, also recently lost its PR head on the agency side, MWW’s Eric Villines. Villines now works for Microsoft as Director of Public Relations for Windows Phone 7 marketing.

Meanwhile, HP issued a press release today naming Stephen DeWitt SVP and General Manager of the webOS Global Business Unit. That means that Jon Rubinstein is out as head of webOS more or less one year from the day that HP acquired Palm, for whom he served as CEO at the time. A former Apple employee instrumental in the development of the original iPod, Rubinstein was brought in by Palm’s board in 2007 and helped develop webOS and the Palm Pre, both of which got the company back into the mobile game despite some questionable business and marketing decisions and widespread manufacturing quality issues. HP’s acquisition of Palm last year was greeted with much optimism by the tech press – yours truly included – and the company’s first webOS-focused products were launched to critical praise earlier this year. After taking several months to make it to market, however, the first HP webOS devices – the Veer smartphone and TouchPad tablet – were greeted by mixed reviews, and the platform continues to trail far behind industry leaders in terms of market share and revenues. The third device introduced this year, the flagship Pre 3 smartphone, has yet to receive a firm ship date, price, or carrier partner.

Rubinstein “today assumes a new role as senior vice president for product innovation for the Personal Systems Group. In this capacity, he will be able to leverage his experience with consumer products to propel innovation across a broad range of areas in the Personal Systems Group,” according to the Official HP Palm Blog. Sounds like a demotion, though you never know – Ruby could find a home within HP working on broad-scale vision sorts of strategy as well as new product initiatives. Or he could be headed out the door. As for DeWitt, he’s got a track record as an operations guy who grew his former division’s profits and marketshare. Efficiency and quality control? Profit and market share? Sounds exactly like what webOS has been missing, frankly.

The blog also notes that the internal transition to “HP webOS Global Business Unit” is underway, which means the end of “Palm” in “HP Palm.”