HomeCanvasr, a platform that lets agents market properties under the radar to a group of buyers who pay for access to off-market listings, has relaunched in Brooklyn, New York. The startup's platform lets buyers see homes that are not listed on any local listing service, joining a slew of technologies that are loosening listing services' grip on for-sale inventory. Social media networks, internal broker communication systems, and, more recently, Zillow’s “coming soon” feature, are all providing means for homeowners to market or sell their homes without the help of a multiple listing service, prompting debate about whether such tools are good or bad for the industry. HomeCanvasr allows agents or homeowners to premarket homes before listing them in a local listing service or t...