The Obama campaign is all but ignoring lawn signs in some battleground states -- so they can focus on silly things like voter registration -- and it's starting to backfire in Virginia. From my anecdotal survey of two voters, it's also starting to piss off Ohio supporters, too.
I think the campaign is underestimating how emotionally attached people are to signs, especially in swing states or conservative areas. It's not just about declaring your support: it's about saying "Fuck you"* to your neighbors, because you're freaking tired of hearing the 19 percent-ers impugn your patriotism.
* I am not implying that my mother would actually say "Fuck you" to anyone.