Someday soon, cars will be rolling Internet access points. Different technologies that exist today could make it happen, such as an iPhone-like connection that picks up Wi-Fi when in range of a hotspot, then switches over to a cellular network when necessary. Or it could be through WiMax, a solution I've heard mentioned by automotive parts suppliers. There are a lot of obvious benefits, such as keeping navigation system maps and points of interest up to date, or having cars serve as traffic probes, reporting to a central database where traffic is slowed or stopped.
But what about the consequences? Back in 1995, when office computer networks started getting connected to the Internet, nobody could predict the wide range of things people are doing on them today. But given this available hindsight, I've got some ideas about what people might do in their Internet-connected cars, and how it all might play out.
Consequences of the Internet-connected car?
Local searchWith a search engine connection, you could be out in your car and realize that you need to pick up garbage bags. So you enter the search term "garbage bags" into your navigation system, and get a list of nearby hardware and home stores. Of course, with Internet search and our modern attention spans, you might get distracted by this Wikipedia article on
space debris, which comes up as part of the Google results. It's an easy link from there to this
diagram of all the junk floating around our planet. And pretty soon you're looking at maps of Antarctica, completely forgetting your need for garbage bags.

Don't let your cat take over your Internet-connected car.
Social networking
If you use Twitter, the Internet-connected car is a real boon, as you can keep all your friends (who don't really care, but are too polite to tell you) notified where you are driving, what music is playing, and whether you feel frowny or smiley. Flash mobs would become flash traffic jams, as everyone drives to a meeting point. Likewise, your car would become an integral part of your MySpace page, since you could update it during the flash traffic jams.
Instant messaging
Various forms of instant messaging existed almost as soon as the first computer network was set up, so of course, this application will find its way into the Internet-connected car. Let's assume some safer interface that wouldn't involve a heads-up projection on your windshield completely obscuring your view with messages from six or seven buddies. Of course, you will want your IM handle on your license plate, but to prevent duplicate plates, they will have to come from service providers, such as AOL and Yahoo, rather than states. And when you're speeding down the road with your AIM license plate proudly showing your "Kewl D00d" handle, the highway patrol can message you with "lol kewl d00d you 2 fast. slow down ;>."

Is this my game or the view out my windshield?
Photo galleries
Cameras are already popping up in cars, from rear-view to lane departure warning systems. Why not add a few more and use them to post photos to Webshots or Flickr from your Internet-connected car. You could quickly post spy shots of new car models out for road testing. And you could bring the cat along for a ride and post funny pictures to LOLCats.com of it staring longingly at a fast food joint, with the caption "I can has cheeseburger now?"
YouTube
Most of the links sent around today point to funny videos on YouTube, but what happens when drivers try to watch the latest Shoes parody on the road? We'll need to set up a special YouTube lane, enclosed on both sides with steel walls, where people won't need to worry too much about steering.
Online gaming
Dedicated gamers play every chance they get, getting online as soon as they come home from work and signing off around breakfast time. So, of course, they will want to continue playing while on the daily commute. And this fact will lead to a spike in popularity of racing games.