Audience-targeted broadcasting is basically the notion that microblogging is more brief and has a reduced threshold for sharing.  This means that people within the microblog know their audience and can be more specific with their words.  A microblog in contrast with a company-wide site can have a shorter amount of information with less explanation because the people within the group know that the others will understand. It can be more project-specific and be code-y in wording.