The commercialization of space is the surest and quickest way to get us there. Advertising has often been on the cutting edge, often the first to fully exploit new technological areas. Advertising is in many cases the first business model that can succeed in a new realm of technology. This then paves the way for future endeavors that require a critical mass of infrastructure and procedure before they can become financially successful in turn.
Our civilization MUST get into space in a commercialized and profitable way as soon as possible. Only through commercialization, led by advertising if necessary, can the resources of space be fully exploited for the good of all. Only through commercialization can the benefits of space travel be brought to the level of everyday use by average people.
In addition, the FAA cannot directly control how space will be used except by US citizens. If the US bans space advertising, then some other country will do it. Banning this will only drive the commercial interests to other, less restrictive countries. This would deprive US businessmen of a perfectly legitimate benefit from the exploitation of space. It will hurt US businesses without accomplishing anything beyond a bit of a delay as other countries catch up to the levels of technology available in the US.
I urge the FAA to abandon this proposal, and keep space open to private use to the greatest extent possible.
What I left out of this, because it would fall on deaf or outright hostile ears at the FAA, is the fact that they have no business regulating such a thing. If I can get to space with a giant billboard, then it's my right to do so. For a US agency to claim jurisdiction or ownership over property in space is ludicrous. Space is wide open, in a legal sense. It is not part of any country, and it is not yet anyone's property.
What is urgently needed is a legal infrastructure to define and protect the private propety rights that will be established in space. There's some tricky issues there, as the natural "land" in space falls in a range of possible orbits around the earth and other bodies, as well as at the LaGrange Points, and on the surface of other bodies themselves.
I'd be fine with private agencies taking up this function. In fact, I would prefer that it not be the government. But it needs to be done soon. Right now, there is no even theoretical definition of property rights in space. If we leave it to the US government, or worse, to the UN or some coalition of governments, we will end up with state claims of jurisdiction over the entirety of space. This would be worse than having no legally protected private property rights, it would extend the reach of governments' active denial of private property rights to space, greatly slowing the process of turning space into a useful and productive resource.
Private exploitation will happen, and that is a good thing. The FAA cannot stop it, but it can delay it by decades or even centuries, to the detriment of everyone.
UPDATE: Apparently, there has actually been a proposal to put a billboard into space that would be as large and bright as the full moon (as seen from Earth). Of course, the astronomers were outraged. And I sympathize, I like seeing the stars on a moonless night myself. But what right can someone possibly have to ban something just because they can see it?
OK, if someone wants to put up a celsetial curtain to block out the sun (ala Montgomery Burns, as one slippery-slope commenter to another site proposed, probably tongue-in-cheek), I could see an argument that since life on Earth would be extinguished, that perhaps we all have a right to sunlight.