Advertising works. Hence the lead story in USA Today:

Prescription-drug ads prompt nearly one-third of Americans to ask their doctors about an advertised medicine, and 82% of those who ask say their physicians recommended a prescription.
The findings in a national survey by USA TODAY, the Kaiser Family Foundation and the Harvard School of Public Health come as drug advertising hit a record $4.8 billion in 2006, up from $2.6 billion in 2002.

In another study, beer drinkers who see signs in bar windows that promise “free beer” are more likely to enter those bars.