From Homestar Runner Wiki
A wooden telephone pole is often used by the inhabitants of Free Country, USA to display various posters and flyers. Because of its frequent use, its midsection is littered with dozens of staples and small scraps of paper. It has also been seen supporting a time clock, which the main characters used as they returned from their summer vacations, although this may not have been a permanent feature.
The hanging of the Strong Sad Lookalike Contest banner in impression suggests that there are at least two telephones poles located in The Field, although they are never both onscreen at the same time.
In A Decemberween Mackerel, it is revealed that a pole is decorated every Decemberween for "The Annual Lighting of the Lights Attached to a Pole in a Tree-Shaped Fashion." This display apparently creates enough Decemberween cheer to cure illnesses, curing Coach Z of "hot pooey," "rub rash," and "chronic athlete's tongue" in 2007, 2008 and 2009 respectively. However, it failed to improve the health of Senor Cardgage.