On-line advertising and marketing services; On-line advertising on computer communication networks; Advertising by transmission of on-line publicity for third parties through electronic communications networks; Dissemination of advertising for others via an on-line communications network on the internet; Providing an on-line searchable database featuring classified ad listings and employment opportunities; Providing on-line directory information services also featuring hyperlinks to other web sites; Operating on-line marketplaces for sellers of goods and/or services; Providing a searchable online advertising guide featuring the goods and services of other on-line vendors on the internet; Providing a web site that enables users to post items for sale through on-line classified advertisements; On-line business directories, being an on-line listing and not on-line publication, featuring housing related, retail shopping, art related, and scientific laboratory business listings; Providing an on-line commercial information directory on the internet; Providing an online commercial information directory on the internet featuring information regarding housing, shopping, arts, and science businesses; Online auction services; Real estate marketing services, namely, on-line services featuring tours of residential and commercial real estate; Promoting the goods and services of others by means of operating an on-line shopping mall with links to the retail web sites of others