We have received a few inquiries about mailed letters to "Springbank Hill Neighbours" regarding Nextdoor. A web search showed: "Nextdoor is a social networking service for neighborhoods. Based in San Francisco, California, the company was founded in 2008 and launched in the United States in October 2011, and is currently available in 11 countries. Users of Nextdoor submit their real names and addresses to the website."
While it appears this social media may be legitimate, as usually advised, caution is always recommended.