They very much frown upon such practices. Check with your ISP if they allow you to be on for long periods of time without them complaining or cancelling your service. DSL uses your existing phone lines and allows you to use your phone in the normal manner even if you are on line. The advantage of DSL is that it is just you on the connection. Very few places geographical wise offer DSL as of yet.
Most systems offer static IP addresses, but more new ones are now using dynamic IP addresses.
Very much recommended for Telnet BBS and other Internet services you may want to run. Cable Modem Service Cable Modem services are becoming more and more common in large and not so large cities. Cable modem services use your existing Cable TV coax line. You can watch TV in the normal manner at the same time you're on the Internet. It is a high-speed Internet connection, though speeds vary greatly from system to system.