Richard M. Smith has written an excellent piece on what companies can learn about you from banner ads. He writes:
I have been tracking over the last couple of months, what information is being sent from my own computer to DoubleClick ad servers. I chose to focus on DoubleClick because they are largest provider of banner ads
on the Internet. Their servers currently send out more than a billion banner ads every day according to a recent company press release.
I used a packet sniffer to do
the monitoring. I found more than a dozen examples from different Web sites of information being transmitted to DoubleClick that most people who consider rather
sensitive. All this information can be tied to me, because all transmissions to the DoubleClick ad servers also include the same unique ID number in a DoubleClick
cookie. I found both personally identifiable information and transactional data being sent to DoubleClick servers.
Personal data I saw being sent to DoubleClick servers included:
My Email address
My full name
My mailing address (street, city, state, and Zip code)
My phone number
Read on, it\'s scary... -- Read More