Internet Service Provider, ISP
From the Wikipedia Internet Service Provider article:
An Internet service provider (ISP) is a business or organization that offers users access to the Internet and related services. Many but not all ISPs are telephone companies. They provide services such as Internet transit, domain name registration and hosting, dial-up access, leased line access and colocation.
ISP connection options
Generally, an ISP charges a monthly access fee to the consumer. The consumer then has access to the Internet for an un/limited number of hours, although the speed at which this data is transferred varies widely.
Internet connection speed can generally be divided into two categories: dialup and broadband. Dialup connections require the use of a phone line. Broadband connections can be either ISDN, Broadband wireless access, Cable modem, DSL, Satellite or Ethernet. Broadband is always on (except ISDN that is a circuit switching technology), and varies in speed between 64Kb and 20+Mb per second.
In the early 2000s, ISPs in the United States faced serious challenges. Telecommunications and IT-related stocks fell sharply, and many ISPs were forced to close, restructure, sell, or merge. Some telcos like Worldcom were spectacular collapses. The slower-than-expected growth of broadband services and key decisions on broadband open access matters all added to the industry’s problems.
By late 2005 a 1Mb connection was being described as slow within the United Kingdom. Many modern software add ons demand minimum speeds of 256K or 512K. With the increasing popularity of file sharing and downloading music and the general demand for faster page loads, higher bandwidth connections are becoming more popular.
Virtual ISP
A Virtual ISP (vISP) re-sells to the general public Internet access purchased from a wholesale ISP. The vISP’s role is to provide any services beyond Internet connectivity, such as e-mail, web hosting, and technical support. The vISP must perform all authentication and accounting functions necessary to provide access and then bill their users for it. This model allows for larger ISPs to increase returns on their investment into what is generally a geographically large, high capacity network, a network which smaller ISPs, as customers of the larger ISP, can use to serve customers in locations that would previously have been unavailable to them.