Can I get service at my home address? (You need to be within a certain distance from your local CO, and need to have "twisted pair" phone lines, not old copper lines, in your house.)
Do they mainly serve businesses or residences? For instance, most DSL companies in the San Francisco Bay Area are for business and are not family-friendly in prices or service orientation.
What's the monthly charge? Who bills me for this? Are there any separate phone line charges? Does it include ISP charges as well as line charges? Is this a flat rate charge, or is it based on my usage of network services?
What kind of computer do I need/do you support? If I have a computer which you do not support, do you have pointers to other sources of information that might be helpful?
What kind of technical support do you offer? Is it available 24 hours a day, seven days a week, or during the ISP's business hours only?
What are the installation charges? Is there an equipment charge? (Typically a modem, possibly a telephone line splitter) What's the labor or installation charge?
Who will do the installation? How long will it take before they will do the installation? How long will the installation take? If there are unexpected problems, how long might it take to resolve?
Are you offering any specials on installation or monthly service?
How many network providers do they have? What kind of connections does your ISP have to each of these providers? For example, if your ISP is MCI, and MCI is its own provider, and MCI goes down (which it does sometimes), you'll be out of luck. Another example is if your ISP has only a couple of smaller incoming network lines (say, two or three T-1 lines), will that (3 to 4.5 Mbit per second) be enough to serve the thousands of subscribers that they have? (Not if they're promising you 1.5 Mbit/sec in at least one direction.)
How many email boxes do you get? Are extra email boxes available? How much will extra boxes cost for other family members?
Do they include a dialup account, so you can get your email when you're travelling out of town?
Do they give you any storage space on their server? You may want to put up your own Web page with the baby pictures or other information.
How many IP addresses? Multi-PC households are becoming very common. Does your ISP charge more for having more than one IP address? If only one IP address, do they support multiple PCs in the home, or do they forbid it? Do they permit it but leave you to figure out the details of your own home network? This includes how to set up a firewall, a hub, network address translation, setting up your own proxy server, and the like. If you've never heard these terms before, the task of setting it all up may be a challenge.)
If they support additional home networked computers, is there an additional cost of supporting more than one PC?
Do they provide shell access? Does person answering the phone know what shell access is? Shell access is a UNIX term for an interactive user interface that allows a user to execute commands. Shell access is similar to the DOS C:\> prompt.
You may not need shell access, but it's a bad sign if your ISP doesn't know what it is. In a Dec. '99 survey, a Flashcom technical support person answering the phone didn't know what it was.
Do you understand their Terms of Service document? If not, can they explain it to you?