The signs are sponsored by an organization called "Francis Marion" named after the South Carolinian revolutionary. They describe the putting up of these billboards as a "coup de main" which is a coup that relies on multiple simultaneous attacks and the element of surprise.
Considering the many complaints that have been made about the billboards by local and non-local residents, as well as taking a look at their websites, the billboards haven't inspired the glorious revolution the sponsors have hoped for, but rather anger and laughter.
There's a poll on the website that asks "Do you believe the White House supports racism?" The poll has been open since July 13. As of this writing, 49.6% of the respondents say that either the White House is not racist, or that it's the Tea Partiers that are the racists. 48.8% either say that the White House directly or indirectly support racists or that the Obamas themselves are racist.
In their "mission and direction" they describe the titles "Liberal" and "Progressive" to be fake titles; a veneer used to mask their real intentions of being socialists and Marxists. Confusingly they describe the founders - and themselves - as "True liberals." You figure that one out.
Some more things to figure out is that they describe themselves as "partisans," that is to say that they are a group of militant supporters of a cause or idea or they are members of a group who attack or harass members of opposition groups. And despite putting a definition of partisan like that on their website, they say they don't support violent acts of any kind. That's nice, but the military images doesn't reassure me.
The rest of their website is pretty typical tea party stuff, with pointers on how to set up your own hateful billboard and where to find the billboards it has put up. The last thing I'll mention is one of the groups it likes on its Facebook page: "If only mosquitoes sucked fat instead of blood."