Ben McConnell and Jackie Huba's Citizen Marketers: When People are the Message outlines the impact of "social media" on marketing practices -- with sometimes dramatic and unexpected results.
Most of the examples cited in the book are business-to-consumer and none specifically tie to the construction industry (the focus is on retailers, branded goods such as soft drinks, and movies and entertainment). The reason in part is the "one per cent rule" -- the authors suggest, for all the noise, only about one per cent of the 'target market' for various Citizen Marketing initiatives actually gets involved. Of course, the one per cent can be a big actual number with popular music or national retailers -- but you are going to find only a handful of people (authorities) with the resources to build a bridge, hospital, or for that matter, to complete a small tenant fit-up. (The numbers may be higher for home builders and residential renovations, of course, but I don't think this sector is at the forefront of mass citizen marketing just yet.)
Then why is the topic important and relevant here -- it is, I think, a signal of the future and represents the importance of new and more challenging influences in decision-making processes. While you aren't going to get a mass outpouring of responses to your construction marketing initiatives (after all, this is a niche market), it is always helpful to know something about the larger world.
The authors' blog is going into my bookmarks -- however, in line with this blog's scope, I won't permalink it as it obviously is not specifically focused on the construction industry.