Lost your dog? Need a babysitter? Simply want to meet your neighbors? Nextdoor, a private social network for building more connected neighborhoods, can help you do all of these things. The startup has landed $18.6 million in venture funding at a valuation of over $100 million to grow its team. Benchmark Capital led the charge on the financing, which also saw participation from DAG Ventures, Greylock Partners, Shasta Ventures, Allen & Company and Pinnacle Ventures.