Why Make an Instructable?
In 2000 I did a project to both cover these ads and, with luck, get the neighborhood to think about why ads filled our public spaces as opposed to anything else more productive. I know I haven't exhausted the potential of this technique, and so I pass it on to you to put to use and improve on.
What's wild posting? If you live in an urban area you've probably seen poster sized advertisements on the streets. These wheatpasted "wild postings" * are often illegally placed on construction site barricades, building facades, in alleyways, and on assorted buildings in order for big business to reach urban demographics (like you!). Companies win by putting their products in the face of hip, urban consumers at the expense of alternative uses for public space - such as murals, street art, community boards, or just plain old architecture. (see Banksy's The Joy Of Not Being Sold Anything)
These top-down autocratic messages designed to persuade the public just become a default part of city life. The idea of something more democratic or of community interest in it's place becomes hard to even imagine.