Advertising of commercial or residential real estate; Matching consumers with real estate professionals in the field of real estate services via computer network; Negotiation and renegotiation for others of leases and subleases and real estate purchase agreements; Providing marketing services for real estate sales; Providing real estate leads for prospective purchasers; Providing real estate video tours for marketing purposes; Real estate advertising services; Real estate auctions; Real estate marketing analysis; Real estate marketing services in the field of real estate; Real estate marketing services, namely, on-line services featuring the promotion of residential new construction, which also contains back office solutions for builders; Real estate marketing services, namely, on-line services featuring tours of residential and commercial real estate; Real estate sales management