John asked if he and his neighbor could save money by sharing one Internet account, via Wi-Fi.
This should work, but the negatives probably outweigh the positives.
The basic concept is simple: You (or your neighbor) subscribes to an Internet service through your phone or cable company. You set up a router with secure Wi-Fi (which you should do, anyway), make sure you have a powerful enough signal to reach your neighbor's home, and give them the Wi-Fi password. Then the neighbor cancels their Internet service, accesses the Internet through yours, and pays you a monthly fee.
Both of you would take a performance hit, but that will only occasionally be a serious problem--for instance, if you're both streaming HD video at the same time. And even that can be easily fixed by paying for greater bandwidth. Many services only charge an extra $5 a month to double your speed.
So what could go wrong? Plenty.
First of all, how well do you trust your neighbor? And their kids? They could download something illegal, such as child pornography, and it would look to law enforcement agencies as if you're the culprit. And since you'd be sharing your local network as well as your Internet connection, they might be able to hack into your hard drive.
And what happens if the neighbor with the service is on vacation when a problem develops? My DSL connection died while I was writing this post. I rebooted the modem and router and everything was fine. What if this had happened while I was on vacation and my neighbor depended on my connection.
Finally, your ISP would almost certainly object. After all, they're losing money in this arrangement. If you read their Terms of Service, you're bound to find something banning such behavior. If they catch you, the consequences might be serious.
All things considered, I don't think it's worth the risk.
Contributing Editor Lincoln Spector writes about technology and cinema. E-mail your tech questions to him at firstname.lastname@example.org, or post them to a community of helpful folks on the PCW Answer Line forum. Follow Lincoln on Twitter, or subscribe to the Answer Line newsletter, e-mailed weekly.