Cobroke Nation asks, 'What are you showing now?'

Site aims to be 'Twitter of real estate,' but biz model has critics

Robin Greenbaum was talking with a friend last year about an idea for a new business last year.

She had a vision to build a real estate version of Facebook, she recalled. Not convinced that would work, the New York City Realtor hatched another idea. "My ‘ah-ha’ moment was, ‘I don’t need Facebook. I can build the Twitter of real estate.’ "