The more noise Yahoo! makes about re-organizing and streamlining its product and sales groups, the more top-level managers head for the exit.

The queue out the door has grown ever since the veteran Internet company began its first re-tooling attempts in December 2006, but continues in the wake of Chief Executive Terry Semel's swift departure June 18.

The latest to leave: Wenda Millard, Yahoo!'s chief sales officer. She left for a new job on Monday, taking with her much of Yahoo!'s knowledge and expertise in turning banners and other display ads into cash. "This is a significant loss given Millard's prominence and standing in the broader online advertising community," writes Cantor Fitzgerald analyst Derek Brown. At the same time, the company said it was merging its search and display ads teams into one unit--a smart move that may have come too late.

Yahoo! can't afford to lose much more of its high-level talent base, but as the company's ongoing structural changes continue--seemingly without much forethought or long-term planning--other key executives will continue to beat a path away from Silicon Valley.

Millard ducked out before Yahoo!'s second-quarter earnings announcement, slated for July 17. Yahoo!'s report that day won't be spectacular. The company has already warned that its revenues will be closer to the low end of its guidance (approximately $1.2 billion), due to a slump in display advertising. Many prime advertisers are spending chunks of their display budgets on social networking sites like Facebook and News Corp.'s MySpace.

Yahoo! has already ceded much of the search ads market to Google, so it shouldn't give up its historical strength in graphical ads without a fight. Google's ready to compete in that arena as well--its $3.1 billion deal to acquire display ads company Doubleclick (a company Millard co-founded) is nearing completion.

Millard could've helped Yahoo! win back ground in display ads, but instead that task will fall to David Karnstedt, the new head of North American sales, and his boss, Gregory Coleman, executive vice president of global sales.

If Karnstedt and Coleman can't renew Yahoo!'s supply of display ads, it wouldn't be out of character for Yahoo!'s directors to blame them. Coleman joined the company in 2001, the same year Semel arrived to build the company back up from the beleaguered bust days. He might be viewed as a throwback to that now ousted regime.

But other prominent executives outside of ad sales could decide to jump ship in the wake of Yahoo! co-founder Jerry Yang's ascension to the chief executive post. Three worth watching: Jeff Weiner, Brad Garlinghouse and Marco Boerries.

Jeff Weiner

Network division executive vice president and a former protégé of Semel, Weiner seemed primed as far back as December for a C-level role at Yahoo! Earlier this year, when Yahoo!'s plan was to divide the company into three operating groups, company-watchers expected Weiner, a search expert and manager of social sites like Flickr, to be tapped for the head of audience role. That job went unfilled and many believe Weiner could soon outgrow his current role. How much longer can an industry-savvy, charismatic up-and-comer stay at a company without rising to a top leadership rung?

Brad Garlinghouse

One ironic possibility: the departure of Garlinghouse, a senior vice president and the guy who penned the infamous "Peanut Butter Manifesto." The memo called for a 20% reduction in Yahoo!'s head count, among other things. The company took at least some of his many suggestions seriously, including his directive to stamp out redundancy: The company is in the process of shutting down Yahoo! Photos, which was viewed by many as photo-overkill when paired with photo-sharing site Flickr. But if Garlinghouse doesn't get a promotion in exchange for his strong opinions and good advice, he could decide his skills would be better used as the leader of a startup.

Marco Boerries

Yahoo! should be doing everything it can to retain Boerries, executive vice president of its connected life division, which runs mobile products. Mobile is one area where Yahoo! might still have a chance at beating Google. While Google bested Yahoo! in overall use of its mobile sites in April, according to M:Meterics, Yahoo! still dominates in mobile e-mail, a growing category as even standard cellphones gain the capability to successfully access the Web.

Boerries not only understands what mainstream cellphone owners want to do with their devices--as evidenced by the popularity of the company's mobile software suite Yahoo! Go 2.0--but he is also a serious tech mind (he sold software to Sun Microsystems at the age of 16), a valuable asset for a company that is so often criticized for losing its innovative edge.