Perhaps the most fundamental interaction in the industry is between the tenant and landlord. There are, however, usually intermediaries (brokers) that facilitate the consummation of the relationship. Thus it gets a little complicated.
Resources such as LoopNet and ROFO that aggregate property listings and make them available to the general public seek to cut out the middle man in a way, but I am skeptical that these are not just MLS and CoStar equivalents with bells and whistles such as augmented reality offered by mobile apps. My hunch is that landlords will benefit from the power of social media more than tenants. After all, they are always searching for new deals, while tenants, especially those active on Twitter, deal with real estate when they have to.
Every landlord should hire a social media marketing manager who follows existing and prospective tenants on Twitter, blogs about new things happening within their portfolio, and makes sure LinkedIn connections are made between asset managers and tenant decision makers.