If I was looking for a job and found a job ad with no contact information, I would see it possibly as spam/scam/non-serious recruiting activity unless I have had heard of the company (in that case I would be looking at their career section anyways).
I'd have to agree with you there. I also remember the last time I was out of work, any job listings without contact info was removed pretty quickly as spam. The job I did end up taking didn't list the company name, which actually kept me from applying for the job for two weeks. I did end up applying in the end (mostly because I wasn't seeing very many jobs that appealed to me, and the job description for this one did look good.) Prospective employees need to learn how to properly apply for jobs, but by the same token, employers need to learn how to properly post their job openings.
Especially if they wanted to charge me $1 for applying...
I know, gaining trust is a huge issue for me. Only Google can get away with doing billboards across highway :)