When Mary Barker was given a global positioning device for Christmas she had no idea what she was getting herself into.

"I have trails up behind my house and I wanted to map my trails," Barker told CTV's Canada AM. "But I didn't have a clue how to use it. I'm not a techie person at all."

However, Barker, a hiking enthusiast and a Girl Guide leader for more than 30 years, not only learned how to use the device at a college course, but was soon turned on to the fact that it is a critical component of geocaching.

Barker became so intensely involved in the activity that she has even gone as so far as to start her own geocaching academy.

But what exactly is geocaching? Geocaching is an activity that is an online scavenger hunt of sorts that began around seven years ago and has a process and a set of rules enthusiasts abide by.

It involves a package, commonly referred to as a "cache" being concealed in a secret location on public land. The satellite coordinates of the package are then posted by the person who planted the package online to the website www.geocaching.com.

Geocaching enthusiasts can then see the satellite location on the site and then proceed to go about searching for the package in an online scavenger hunt using the posted coordinates. All they need is an Internet connection, a handheld global positioning device (GPS) and a boundless curiosity to search for the package.

"You start off usually with a town name or a postal code," said Barker. "And you decide that that's the radius you want to work in. When you punch your postal code into the Internet, it comes up with a list (of caches) that are closest to you to furthest away within a hundred mile radius."

Geocachers will then embark on a search to find the package and get as close as the global positioning systems will allow them.

"A GPS is only accurate within 10 metres," Barker said. "So once you get that close, you might as well put the GPS down and just look around and say, 'If I was a Tupperware container hidden in a bush, where would I be?'"

The packages are usually labeled with a green "official geocache" label on them.

The size of a geocache can either be very large or very small and are referred to as macro-sized and micro caches respectively.

A cache is usually packaging in camouflaged and waterproof packaging.

Typical items may include a thermometer or a flashlight or mementos referred to as geocoins. These are registered markers that can be traced and followed on www.geocaching.com. In addition to these various items, there are things that are usually present in every cache.

"There's always a logbook and a pen and pencil," Barker said. "You always sign the logbook because you want proof that you were there."

Geocachers can take items from the package, but it is an understood rule among geocachers that the item taken, is replaced with an item of equal or greater value so that there will be an item for another person who also decides to seek out the package.

After finding the cache, geocachers commonly post on geocaching.com about their experience in finding the package. According to Barker, these logs should be read before embarking on a geocaching mission because they can provide pieces of information that may be invaluable in locating the "cache."

Because of the geocaching.com website, enthusiasts can literally indulge in the activity around the world. And they do. There are an estimated 200,000 caches around the world with three-quarters of them in North America, according to the Canadian Press.

In Canada, estimates of cache sites number over 7,000. Quebec is estimated to have 6,400 and B.C. is believed to host 5,500 sites.

It's an activity that is growing so much in popularity that Parks Canada has had to implement an interim policy regarding the practice of geocaching.

The Parks Canada interim policy prohibits the placing of cache packages and has placed and has gone about removing existing physical caches.

"The critical issue around geocaching is that people are taking something and leaving it in a place," Ed Jager, manager of visitor experience products and services at Parks Canada told CTV.ca.

 "So they're taking a container or whatever and they're leaving it someplace and Parks Canada has done lots of work around trying to get people to leave no trace when they go into the environment and to pack out what they pack in. So here's an activity that seems to run counter to some of that ethic."

While Parks Canada has encouraged waymarking or the use of virtual caches, where the actual package could be an existing landmark or a building to be located for educational purposes, Jager said that this activity can be underwhelming for geocaching enthusiasts.

"It doesn't carry the same enjoyment factor," Jager said. "Probably a good quote from our working group was 'Virtual geocaching is kind of like golfing without a golf ball.'"

Parks Canada, in conjunction with members of the geocaching community, as well as environmental and tourism representatives, formed a working group to formulate a new policy regarding geocaching which is set to be unveiled in the very near future.

Some of the concerns of Parks Canada in reference to the activity include wildlife locating and opening cache containers and the fact that people engaging in the activity may be putting themselves at risk trying to find caches in areas that are not easily accessible.

Despite these issues that can potentially limit the practice of geocaching, the practice is growing by leaps and bounds and has even begun to sprout its own vocabulary.

A "muggle" or a "muggler" is a term borrowed from J.K. Rowling's Harry Potter books and refers to someone new to the geocaching community. Often notes for their benefit are found in cache packages. Another term is a "hitchhiker" which refers to an item that is supposed to be moved to a new cache when it is found.

The increasing popularity of geocaching is representing a boom for Mary Barker and the town in which she lives. Last year, Wilberforce, Ont. and some of its surrounding communities decided to bestow upon itself the title of being the "Geocaching Capital of Canada," in an effort to boost tourism to the area.

Local businesses have certainly taken to the name with restaurants selling geo-burgers and hotels offering geocache getaway packages.

Additionally, the post-office that Barker helps to run sells many trinkets which could be used to leave in caches.

Describing a recent seminar at the Geocaching Academy of Canada attended by around 50 people with an average age of 60, Barker said the activity was picked up immediately, crystallizing geocaching's appeal and intuitive ease.

"We were a little nervous that this is not a techie crowd, 'this is going to be hard'" Barker said. "But they were amazing. They caught on and they went and found all the caches that were hidden around the park."

With files from The Canadian Press