Initial conversations were through former colleagues from another company and then through the HR department. The formal interview process began with phone screenings and conversations with various engineers, the sales director and others in the company. They seemed genuinely concerned about building a solid company around the technology they focused on, therefore they seemed to be checking for both technical competence as well as an aptitude for communications and sales skills.
The one-on-one interview was with the CEO who was fairly new at the time. My perception at the time was that he was more "generic biz" with a focus on bringing the company to profit and then public. I was not exactly impressed with his understanding of the geospatial industry, but he had been successful (as I learned during the interview) in other industries. I felt that it was overkill to be interviewed by the CEO after having so many calls/conversations with others in the company and I later learned that this was par for the course... Caveat: there has been a massive change of leadership so the current CEO is a different person.