Individuals find multiple listing service, or MLS, entries for Long Island, New York, through a Realtor. While the public can access some MLS information through Realtor websites, the data is often limited, inaccurate and out of date, according to About.com.
Real estate professionals pay for MLS; keeping the listings somewhat private gives them an edge in the market. About.com recommends that people who want to find listings give their Realtor a list of criteria, such as number of bedrooms, number of bathrooms and Long Island neighborhood. They then get emailed updates from their Realtor of new listings that meet their criteria.