Every day I receive tons of resumes from individuals with no qualifications related to the job I have posted. It is useless to send resumes blindly to HR professionals in response to an ad for a job which you have no qualifications to perform. Candidates often question why they do not get responses to their resumes. It is because you are applying for a job that you are not qualified for.You are wasting valuable time if you are sending resumes in response to an engineering position and you are an accountant. If you do not match the required qualifications listed in a job posting do not respond to it. If you are close to the position described, it is not a big stretch for you or you have done the job recently... then certainly apply. Hiring managers are looking for specific people for specific jobs with very specific skills. Don't apply to jobs that you would "like" to do all day long. You have to find jobs for which you are qualified.
Better Tactic: Do send your resume to anyone you can find... though send it to them directly. Simply state that you are a great ____ and are searching for a great new position and to keep you in mind. If you see a posting by a recruiter online, find that person's direct email and send them a resume with a nice short cover letter. If the posting lists no contact person or email, find the company's website and apply online or send it to their general HR email box. Or, mail them a copy though the mail! Physically mailed resumes always get priority since they have to handle the resume and at least look at it.
Good luck!