Signals, Truth, Design is the upcoming book of Judith Donath which deals with the social dynamics of the "mediated world" (i.e. email, forums and other communication supported by the Internet) and how to design it. To do so, the author use the "signaling theory" as a framework to describe how:

"most of the things we want to know about each other – one’s identity, status, and intentions – are qualities that are not directly observable. Instead, we rely on signals, which are indicators of these hidden qualities, in order to comprehend the world around us. (...) Signaling theory explains what makes some signals more reliable than others are."

She applies it to some more specific topics such as deception, identity, reputation or impression formation. Why do I blog this? this topic is a bit different than what I am interested in, but awareness (as provided by mutual location-awareness tools) can be perceived as a "signal". This "signal" concept sparked some discussion during my PhD defense when one of the reviewer wondered about why employing this "old" metaphor, very tight to the Shannon-model of communication. The argument was about showing that it's still relevant, I'd be curious to know how this book approach the signal notion using the biology background.