Google lost Google Maps Co-Founder Lars Rasmussen and AdMob CEO Omar Hamoui on Friday.
Rasmussen, who also worked on the soon-to-be defunct Google Wave, will join Facebook. In an interview published today, Rasmussen was critical of Google as he spoke about Wave's failure, and explained decision to quit.
"We were not quite the success that Google was hoping for, and trying to persuade them not to pull the plug and ultimately failing was obviously a little stressful," he said.
"It wasn't something that I would like to bet my life on, but all that excitement we created when we first unveiled the project was based on something real. It takes a while for something new and different to find its footing and I think Google was just not patient."
Another reason he cited for leaving was Facebook's smaller size. Google employs 25,000 staff members, while Facebook (which he called "a sort of once-in-a-decade type of company") has about 2,000.
"The energy there is just amazing, whereas it can be very challenging to be working in a company the size of Google," Rasmussen said.
"He built a fantastic business in a short period of time, and we wish him all the best," Google said in a statement. "Mobile advertising - across search and display - is now a billion-dollar business for Google, with AdMob a key part of that."
As previously reported, YouTube CEO Chad Hurley stepped down Friday.