What audience analysis measurement principles and techniques are most effective and why?

Audience analysis measurement techniques and principles are very important and effective for media companies because they allow them to learn about their audiences. There are many ways for companies to learn about their audiences. There is the survey industry, probability sampling, Quota sampling, evaluating surveys, and latter day straw polls all used for audience measurement. Companies also use many techniques for measuring audience size, which include; newspaper and magazine audits, Broadcast ratings, engagement ratings, basic tools such as interviews and people meters, Internet audience measures, multimedia measures, and mobile audience measures. Companies also measure audience reactions using techniques such as interviews and focus groups, and with new technology companies have been able to do very affective audience reaction measurements using tools like Galvanic skin checks. Media companies can also analyze their audiences by studying demographics, cohort analysis, geodemographics and psychographics.
In my opinion, even with all the new forms of audience analysis and measurement the most effective technique remains to be surveying. The surveying industry is a 5 billion dollar per year business. Clients are big corporations, political candidates, and the mass media. There are about 300 U.S companies in the survey business but the top companies are Nielsen, Arbitron, Gallup, Pew, and Harris. Surveying is very important because it helps companies determine where to place advertisements, what type of programs to run and at what times, which programs will be cancelled, and much more.