A key aspect in marketing is “impressions” - they say it takes about 6-7 impressions for a name (person or product) to stick in someone’s head.
Each yard sign, particularly those which are not strewn across public roadsides but rather placed on private property to represent real support from a real household, makes an impression on every voter who sees it.
In my neighborhood, I’ve only seen one Obama sign, even in the yards of die-hard Democrats displaying big signs for other Dem candidates. And that, likewise, makes an impression.
There are several Obama yard signs in my hood and no McCains, that I have seen.
I am placing my Mccain/Palin sticker on my car today, and I am excited about it. I was not going to do a bumper sticker this election, but Palin has re-energized my support. Of course it will be the only one in the Whole Foods parking lot...