Do you have applications in multiple web sites that your customers use? You can use a portal to give them direct access to your services!
A portal for your business allows you to provide access to multiple services and sites you want your customers to use. This would be a B2C portal - business to customer. An mall site, a group of online stores using one interface, is another example of a B2C portal. A single online store falls under the classification of an e-commerce site. However, some people are blurring the lines to suit their own needs.