Choice of ISP is important both for those looking for Internet access and those looking for a host for a web site. Most individuals and small businesses want to connect to the Internet via their telephones. Their modem dials a number, goes through some hoops, and then they are connected. A few charge by the hour, period. Large, global networks carry Internet traffic.
More cars can move faster on the six-lane highway, all other things being equal.
At a minimum, your ISP should have a T-1 connection. Each computer on the Net has an address. However, an ISP can take one computer with a very large hard drive and give it multiple addresses. Think of Mailboxes Etc. You have created a virtual office.