Gateway Portals: These are generalized portals which take the surfer to other sited of their interest. Eg. Indiatimes, Rediff, Yahoo etc.
Vertical Portals: These cater to specific community or area eg. Sharekhan
Business to Business or B2B: It involves business to business need satisfaction. Eg. Computer component manufactures selling component to an assembler who is not the ultimate consumer of the product but in turn assembles and settle them to the ultimate customer.
Business to Consumer or B2C: Here business reaches out to their ultimate customer. Eg: Netvarsity of NIIT.
Customer to Customer or C2C: These are auction sites which bring together retail customers together. Pioneered by eBay and eAuction involves setting up of forum where sellers can put up products for sale.
Proxy Server: it is an intermediary server which acts as a connecting agent between the internet and work station in a LAN.