An Internet Service Provider (an ISP) is a provider of Internet services. Most telecommunications operators are ISPs. They provide services like internet transit, domain name registration and hosting, dial-up access, leased line access and colocation.
In 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. The slower-than-expected growth of broadband services and key decisions on broadband open access matters have all added to the industry's problems.