Communicating well with the written word
Do have print large enough with enough blank space around it so that the eye is drawn to the message.
Don't plant a tree in front of a sign that blocks it (as a nearby flower shop has done).
Don't put a street sign with dark green background and slim white bars in front of evergreens so that the print blends into the greenery (as the street sign by our house is--used to be medium green background with broad white bars that could be read from a distance).

Hidden advertising messages
It used to be that if you bought a product "people would love you."
Today if you buy a product or service your life will be changed and you "will love yourself."

Male bowerbirds weave intricate display areas (or bowers) out of twigs. They decorate their bowers with charcoal, saliva and colourful objects. Because of this, bowerbirds are often thought of as the most advanced of all birds. A bower is not a nest. It is an attractive 'avenue', used by male bowerbirds to entice a female. When they are not feeding, the males spend much of their time perched in the bower, calling to potential mates and warning off potential rivals. Bowerbirds are very closely related to birds of paradise, and species of bowerbird are found in many parts of Australia and New Guinea. They are mainly forest birds, living in a particular local area throughout their live. See more information plus picture of bowerbird in a bower decorated with mainly blue items at: http://www.environment.nsw.gov.au/animals/Bowerbirds.htm

FEDERAL TRADE COMMISSION 16 CFR Part 255
Guides Concerning the Use of Endorsements and Testimonials in Advertising
Read regulations at: http://ftc.gov/os/2009/10/091005revisedendorsementguides.pdf
Recent articles on celebrity endorsements via Twitter prompted me to find the federal regulations.

Advertising Industry in the Digital Age by Suzanne M. Kirchhoff
Congressional Research Service February 1, 2011
In the 111th Congress, members introduced legislation to limit the tax deductibility of advertising for pharmaceutical marketing and circulated proposals to give consumers more ability to block technology that tracks individuals’
activities online so that marketers may tailor advertising accordingly. House and Senate committees held hearings on privacy issues; advertising and marketing directed at children; and the state of the newspaper industry, which is in financial distress as advertising moves to the Internet and away from the print product. The Senate Committee on Commerce, Science, and Transportation held a hearing on potentially deceptive advertising practices, including false testimonial advertising, blogging, and other areas. Congress passed and President Obama signed legislation to regulate the volume of commercials on television (P.L. 111-311). On the regulatory front, the Federal Trade Commission (FTC) released guidelines calling on bloggers to disclose paid product reviews, and in December 2010 recommended a Do Not Track function to allow consumers to prevent advertising and other firms from collecting data about individuals’ online activities. The U.S. Food and Drug Administration (FDA) is examining pharmaceutical marketing in social networks and could propose guidance for online marketing early in 2011. In December 2010, the Department of Commerce Internet Policy Task Force released a paper on commercial privacy issues. Much of this activity is in response to the rapid growth of advertising on the Internet. Online ad spending has jumped more than 400% during the past decade, to more than $20 billion. The online market is dominated by a small number of firms, with the top 10 digital ad firms garnering more than 70% of all online ad revenues, a level that has remained relatively constant in recent
years. “Search” advertising—where companies sell ads as part of consumer-initiated information queries on web browsers—accounted for nearly half of digital ad revenues in 2009, with Google, Microsoft, and Yahoo getting most of the online search traffic. http://womma.org/diresta/2-10-11.pdf

March 30, 2011 The FDA has once again postponed the release of its first draft guidance for social media. The federal agency was supposed to release the guidelines in late December, but stated at the time that it would delay the release of the first draft guidance until the first quarter of 2011. Now that's been put on hold. http://www.mmm-online.com/fda-again-delays-promised-social-media-guidance/article/199595/

June 8, 2011 The U.S. Food and Drug Administration missed its last two self-imposed deadlines to issue guidance on using social media to promote drugs, leaving pharmaceutical companies at risk of unwittingly running afoul of marketing laws. Drugmakers that set up Facebook fan pages, "tweet" company announcements on Twitter, and post videos on YouTube can reach millions of consumers with their message. But without guidance from the FDA on how to do that, they can also attract unwanted attention from the regulator, according to lawyers who track social media trends. Drugmakers also risk losing customers when their audience can't tell the difference between legitimate companies and illegal online pharmacies. The FDA's Division of Drug Marketing, Advertising and Communications said after hearings on social media in November 2009 that it would issue guidance by the end of last year. http://www.cwsl.edu/content/news/060811_Bryan%20Liang_FDA%20Social%20Media_Los%20Angeles%20Daily%20Journal.pdf