Thanks to a new service, you may not have to ask or answer that question. Glympse, which launched on Monday, joins Loopt and Google Latitude as the newest location-based service that uses cell phones’ GPS capability to tell people where you are.

Glympse, which is free, has taken a different approach. Unlike Loopt, which requires the sender and recipient to sign up for service and download an application, Glympse requires almost no effort on the part of the person who is following you. All they have to do is click on a Web link on a computer or a Web- enabled phone to see where you are on a map.

To transmit your location, you need to download an application to your phone and use the application to send a “Glympse,” which authorizes that person to follow you for a specific amount of time and send them the link they need to see you on a map.

Another way it differs from both Loopt and Google Latitude is that Glympse can automatically time out after tracking someone for four hours. The person being followed can also choose a shorter monitoring window, like 30 minutes.

To its credit, Loopt is also permission-based and sends reminders that you may be sharing your real-time information. Google’s Latitude service, which also requires you to give permission to be followed, only displays your approximate location — within about a half mile — but doesn’t show precisely where you are.

With Glympse, you might not know the person’s exact address, but you’ll probably be within a hundred feet.

The coolest thing about Glympse is when you are following someone on the move. You can pinpoint them on the map, see their speed, and see when and where they stop.

I used it to follow Glympse co-founder Bryan Trussle as he rode in a car from my house to San Jose. I saw him get on and off the freeway and pull into a parking lot. At one point I caught his car’s driver exceeding the speed limit by a few miles an hour.

As he compared his actual location to what I saw on my PC, we found there only a slight lag between the two — a difference of 10 seconds on average.

While I realize that some will consider this technology a little creepy, there are practical uses for it.

Some police departments, delivery services and businesses spend a lot of money on equipment to do what Glympse could do for free.

For one thing, it can reassure parents and family members that their loved ones are safe.

I remember how nervous I was when my 16-year-old daughter would use the car or ride in other kids’ cars. We’d insist that she call us when she arrived and made her tell us where she planned to go. If she had a Glympse-equipped cell phone, we could have checked in on her from time to time — and we would have known if she was speeding too.

And rather than calling people to let them know you’re arriving in 15 minutes, they can track you online or on a Web-enabled phone.

The Glympse’s public beta currently works only on the T-Mobile G1, which uses Google’s Android operating system. The company is working on versions for the iPhone, Windows Mobile and BlackBerry.

Disclosure: Glympse, as well as its main competitors, Loopt and Google, are supporters of ConnectSafely.org, a nonprofit Internet safety organization I help operate.

Even if you are comfortable with the person receiving the image, you never know for sure where else it might land. Digital images are easy to copy and forward and, even if you trust your friend’s discretion, it can be accidentally forwarded or seen by others with access to your friend’s phone or computer. It’s not uncommon for such images to find their way to other people’s cell phones and even Web pages, where they can be seen by anyone, copied, searched for and redistributed, perhaps forever.

For minors, there’s another risk — serious legal consequences. Creating, transmitting and even possessing a nude, semi-nude or sexually explicit image of a minor can be considered child pornography. It can be prosecuted as a state or federal felony and can even lead to having to register as a sex offender.

Crazy as it seems, some prosecutors have gone after kids for taking and sending pictures of themselves. There was a case in Florida a couple of years ago where a teenage boy and girl photographed themselves nude and engaged in “unspecified sexual behavior.” One kid sent the picture to the other and somehow the police got involved. They were tried and convicted for production and distribution of child porn and the teen who received the image had the additional charge of possession. An appeals court upheld the convictions.

In January this year, three teenage girls from Pennsylvania were charged for creating child porn and the three boys who received the images were charged for possessing it. And, according to CBS News, a Texas eighth-grader in October spent a night in jail after a coach found a nude picture on his cell phone, sent by another student.

It’s sadly ironic that the very child porn laws that were written to protect children from being exploited by adults could wind up having a devastating impact on the lives of children who, while acting stupid, have no criminal intent. For some perspective on whether this issue is or isn’t overblown, see Anne Collier’s piece in NetFamily News.

It’s hard to know how prevalent the practice is. But if you believe the results of an online survey commissioned by the National Campaign to Prevent Teen and Unplanned Pregnancy, about 22 percent of teenage girls and 18 percent of boys admit to having “electronically sent, or posted online, nude or semi-nude pictures or video of themselves.” I’m not completely confident about the results of this study, which was carried out by a market research firm and not subject to academic peer review. But I think it’s fair to assume that a significant number of kids are doing this.

Perhaps more interesting than the survey’s overall number is the breakdown of why teens take and send these pictures. Of those who reportedly sent such pictures, 71 percent of girls and 67 percent of boys said they sent or posted content to a boyfriend or girlfriend, while 21 percent of the girls and 39 percent of the boys say they sent it to someone they wanted to date.

As you might expect, peer pressure plays a role. Of those who sent such content, 51 percent of teen girls cited “pressure from a guy,” while 18 percent of teen boys blamed pressure from girls.

While sexting is troubling, I think it’s important for us all to take a deep breath and refrain from passing new laws or using child pornography laws that were designed to protect children from exploitation by adults.

I suspect that sexting will diminish over time. Kids aren’t stupid and, faced with the facts, most will wise up. We also know that kids who get in trouble online are the same kids who get in trouble offline, so when teens repeatedly do sexting or other stupid or risky things online, it’s important to intervene early and often.

The best thing for a parent to do is to have a non-confrontational conversation — perhaps over dinner — to ask your kids if they’ve heard about sexting and what they think about it. You might not get a straight answer but you’ll open up a dialog that can go a long way toward helping your kids understand how to minimize legal, social and reputation risks. There are more tips on ConnectSafely.org, a non-profit Internet safety site I help operate.

Boy, am I glad the Internet and camera phones weren’t around when I was a kid.