Employee referrals are preferred, but I found the company through the job search service Indeed.com. After I submitted my resume electronically, I was assigned to a DDN-retained contract recruiter, who made sure the entire hiring process happened ... presumably for a commission.
I was told that one positive factor in the decision to hire me was the fact that I included links to online published work I had authored. The hiring managers could read my work for themselves and judge both its communicative and technical merit.
After resume screening, there was a telephone interview with the recruiter, then with two hiring managers. After that came an on-site interview with a hiring manager and a potential coworker who could judge my technical and writing chops and assess my fit to the company culture.
When the decision was made to hire me -- a process that took about a month from resume submission to hiring decision -- DDN wanted me on board ASAP. I gave two weeks notice at my old company, which meant putting DDN off, but they understood that. There was no gap between leaving the old company and starting work at DDN.