I don't see much point in complaining about some liberal group spending a bunch of money on a billboard. It won't convince them to change their tactics.

If people want to spread the same message cheaply and more effectively, they can do it themselves. What's stopping you form dropping a banner over the Dan Ryan, Eisenhower, Kennedy, or any other highway? What's stopping you from changing billboards all over town? There are PLENTY of local graffiti artists you could get to help you out, not to mention plenty of other people who'd be sympathetic to your cause.

Actually taking direct action is much better than criticizing someone else's tactics on the internet.