Here is an interesting question and a list of various responses.
The question was: how many media messages is the average American exposed to in a single day.
Look at all of the responses:

Consumers are exposed to hundreds of commercial messages per day in one form or another -- from the boring, copy-laden radio commercial to the easily skimmed, forgettable newspaper ad, and from the billboard on the side of the bus to the logo on the side of the building. My search returned the following results for the number of advertising messages an average American is exposed to on a daily basis. The source and corresponding links for the information I gathered are included:

“The average American is exposed to 247 commercial messages each day.” Consumer Reports Website

According to Alf Nucifora, an Atlanta-based marketing consultant:
“Research tells us that the average American consumer is exposed to more that 600 advertising messages a day in one form or another.” The Business Journal Phoenix Website

In the article ”Practical Advice from the Union of Concerned Scientists” by Michael Brower, PhD, and Warren Leon, PhD: “The average American is exposed to about 3000 advertising messages a day, and globally corporations spend over $620 billion each year to make their products seem desirable and to get us to buy them.” Union of Concerned Scientists Website

“A conservative estimate has the average American consumer exposed to more than 850 commercial messages a day.” Texas A&M University Digital Library

“If you're like most consumers, you have been the target of intrusive marketing and a constant barrage of irrelevant advertising messages. The average American sees over 3,000 advertising messages a day. If you fill out a warranty card, get divorced, buy a home, get listed in a school directory, enter a sweepstakes, purchase an item from a catalog, file an insurance claim, or perform a myriad of other everyday activities, some company somewhere makes a record of this fact and sells it to marketers for profit.” Superprofile Website

This was published in a column at The Newspaper Association of America Website “Not too long ago, the average American was exposed to over three thousand advertising messages in the average day. Today, you get that many before breakfast! Everyone is trying to build a brand. This season, the networks have added one more minute of commercials per half-hour, and that is just the beginning. Have you seen the ads in golf holes (talk about hidden persuaders), in bathroom stalls, on grocery register receipts and even in the sand on the beach?" Newspaper Association of America Website

Excerpts from the article “How Not to Fail at Your Marketing Or, Who's fault is it, anyway?” by Michael Lovas: “The average American is targeted by 3000 messages per day. That includes phone calls, e-mail, meetings, conversations. -- Data Smog by David Shenk” “The average American adult is exposed to over 600 advertising messages in a single 24-hour period. -- Managing Business to Business “Marketing Communications, De Bonis and Peterson.” Each of us sees more ads alone in one year than people of 50 years ago saw in an entire lifetime. -- DMNews magazine, 12-22-97.” Judy Diamond Associates Website

Shenk, in his book Data Smog, states that the average American encountered 560 daily advertising messages in 1971. By 1997 that number had increased to over 3,000 per day. Data Smog Surviving the Information Glut by David Shenk ISBN 0-06-018701-8 (HarperEdge, 1997, $24.00)

A project from the University of Washington: “The average American is exposed to 500 to 1,000 commercial messages a day (Arens 1999). That's anywhere from 182,500 to 365,000 commercial messages that a person will view this year alone.” University of Washington Website

In Chapter 1 of the book “Marketing Without Advertising: Inspire Customers to Rave About Your Business to Create Lasting Success” by Michael Phillips & Salli Rasberry: “It is estimated that each American is exposed to well over 2,500 advertising messages per day, and that children see over 50,000 TV commercials a year.” Nolo's Law Store

Description of a marketing course at Fordham University: “Advertising is the most pervasive element of the marketing mix: the average American family of four is exposed to 1,500 advertising messages a day!” Fordham University College of Business Administration

What is the problem with advertising today? “One problem with advertising today is that there is too much of it. The average American is exposed to over 3000 ads every day. The ads increasingly encroach upon our public space -- our schools, our public transportation, our buildings, and even our beaches (a new technique enables the advertisers to stamp their ads onto the sand at beaches.)"

In the article “High-Profile Product Recalls Need More Than the Bat Signal” by Jeanne Finegan, from Huntington Legal Advertising “Because Americans are saturated daily with marketing messages, product recall and legal notice programs need to shout above the other estimated 3,000 marketing messages we receive daily.”

The following excerpt claims that in the U.S. the average person is exposed to 1,600 advertising messages per day “According to the Nielsen Report the average American home had the TV set on for about seven hours a day. The actual viewing was estimated at 4.5 daily hours per adult. To this had to be added radio, which offered 100 words per minute and was listened to an average of two hours a day, mainly in the car. An average daily newspaper offered 150,000 words and it was estimated to take between 18 and 49 minutes of daily reading time. While magazines were browsed over for about 6 to 30 minutes. (..)Media exposure is cumulative.(..) All in all, the average adult American uses 6.43 hours a day in media attention. (..) The media, particularly radio and television, have become the audiovisual environment with which we interact endlessly and automatically. Furthermore, the barrage of advertising messages received through the media seems to have limited effect. Although in the US the average person is exposed to 1,600 advertising messages per day." Emayzine Website

According to Jean Kilbourne, who has been studying ads' cultural impact for almost 20 years in an interview by Nan Knutsen: “We believe we're not affected by advertising because it is so often silly, trivial, and something we don't pay conscious attention to. We flip through ads in magazines, speed by billboards, zone out during TV commercials. However, advertising's influence is cumulative and primarily unconscious. The less consciously we watch ads, the more deeply we are affected. The average American is exposed to more than 3000 ads a day, and companies spend over $200 billion each year on advertising.
Jean Kilbourne Website

In an article from the California Newsreel Printout: Stuart Ewen, professor of communications at Hunter College, says in the The Ad and the Ego video that what affects us is not our experience of any one ad but of "the totality which repeats certain kinds of messages again and again." This constant stream of messages - 3000 "impressions" a day according to researchers, on television, radio, billboards, buses, T-shirts, sports events, even urinals - forms the neural network of our consumer society. California Newsreel Printout

An excerpt from an outline used to facilitate discussion with the video Still Killing Us Softly, written by Juli Hayes, R.D., University of California, Santa Barbara. About Advertising A. Advertising is a 130 billion dollar a year industry. It is thus a powerful educational force in our culture. 1. The average American watches 30 hours a week. 2. The average American spends 110 hours a year reading magazines. 3. This ads up to exposure to 1500 ads daily. Cambridge Documentary Films

The varying numbers I gathered can be explained in the following paragraphs: Question asked on Monday, June 24, 2002 at The Advertising Media Internet Center: “Do you have any updated information on the number of ad messages the typical consumer is exposed to DAILY?” Answer: “This statistic is only used for "hype" purposes, usually to portray advertising as some kind of social evil. The Guru has recently heard numbers cited between 3,000 and 20,000. These numbers are ludicrous. When challenged, those citing them will hedge and say they meant "informational messages" or some such and include product labels passed in a grocery store. The only way to get a total this high is to do exposure counting by a method that would include, for example the idea that when a person turns the pages in a newspaper's classified section he is exposed to all 500 ads that might be on each spread of those pages. When considering these silly numbers, it is best to stop and think: a person is usually only awake for about 1000 minutes per day. If they did nothing else but look at or listen to advertising, it would take every minute of the day to generate 3000 exposures. A number around 500 might be a reasonable extreme, again counting as exposure all the out-of-home media passed, and small space ads in newspapers and magazines,even thought there may be no notice taken at all." “What are the going numbers for total ad exposures per person per day? Is it possible to break down the average into the different media?” “The Guru has seen estimates from a few hundred to many thousands. The Guru tends to go along with one of the best accepted estimates, that there are about 245 ad exposures daily, 108 from TV, 34 radio and 112 print. Others estimate 3000, 5000 or more. Even the 245 is "potential" and perhaps only half are real exposures. The higher estimates probably include all marketing exposure including being in the vicinity of product labels or actual products with trademarks visible, such as your car, computer, fax, phone, shirt, pencil, paper towel in the bathroom, etc. Just think, if we were really exposed to 3000 advertising messages per day, at an average of just 10 seconds apiece (accounting for radio :60's and brief exposure to billboards), these exposures would consume 8.33 hours out of our 16 waking hours per day.”

 The Advertising Media Inter Center Website Search Criteria:*+media+messages+per+day+&btnG=B%FAsqueda+en+Google&lr=*+++media+messages+per+day+&btnG=B%FAsqueda+en+Google&lr=