The action of conducting commercial transactions online, typically through an online store, where information, goods, and/or services are being sold. Amazon.com is an example.

The practice of contacting prospective or actual customers via email. While sending unsolicited bulk email (e.g. email spam) is contemptible, email marketing can be a very effective method of working with prior customers to retain mindshare.

Similar to the traditional print newsletter, an email newsletter is sent electronically, usually to subscribers or members on a particular email list. Email newsletters can be sent weekly, monthly, bi-monthly, quarterly, or annually.

A set of mathematical algorithms that are used to encode data in order to protect it from unauthorized users. This is a security measure.

Any page within a website that a user uses to enter that website. Can also be considered a Landing Page.

A web page that contains an error message to the visitor. Common error messages include 404 Error.

The last page that a visitor views before leaving a website. The opposite of an entry page.

In Jon Kleinberg’s HITS algorithm (as well as the CLEVER, ExpertRank, and Edison algorithms) an expert is a document about a specific topic for which hubs exist, such that the expert document is pointed to by many hubs. Cf. Hub.

A flexible way to create common information formats and share both the format and the data on the Web, intranets, and elsewhere.

The act of building properly structured links from third party sites for search engine optimization. The opposite of external linking is internal linking. All else equal, external links are more powerful, but internal links are often easier to control. An example of the power of off page optimization can be found through the Google bomb.

A URL that is outside of a particular website, but refers visitors to that website.