Real estate brokerage is an economic activity that uses commissions as the operating characteristics to facilitate the real estate transactions of others, and engages in the provision of real estate transactions, exchanges, leases, replacements, and other information, trust labor services, and intermediary agency services. According to the above definition, which of the following is real estate agents? ['As a community worker, Aunt Zhang often matches people who buy and sell houses in the community.', 'A real estate column is set up on a website to provide services for members who publish renting and selling information for free.', 'An intermediary company accepts the commission of a real estate developer to sell its newly developed commercial housing.', 'Property consultant Xiao Li bought a high cost-effective house through his real estate network.']