Passively Multiplayer Online Game

You've tracked them silently for days, learning their style, their routines, their favourite places. Now you've finally made your move: traps laid, you lurk inside Netflix.com to watch it all play out. Your first mine catches them off guard as they make their Tuesday evening sweep of Major Nelson's site. Your second tags them on the rebound, as, shaken, they head back to your profile to see what else you have in store. But you never find out about mine number three (lodged deep inside Amazon.co.uk, with that expensive toaster they've got a thing for) because with a misplaced sense of victory, you head towards Wired News, and that's when they get their revenge, with mines scattered on both the front page and the GameLife blog. Leaking data points all over Chris Kohler, you sign off, defeated. Welcome to the new internet: this time you're a player as well as a user.

If you've always thought of the internet as a battleground, PMOG - the Passively Multiplayer Online Game - will show you where the lines are drawn. If you've always seen it as more of an open-ended museum, then chances are PMOG will help you find the dustiest secrets. Who knows, even if you mainly log in for head-swaps and UFO footage, PMOG will probably have a thing or two to show you as well. At its best, when it's tangled you together with a rival, and the whole of the web has become your explosive playground, this can resemble the giddy one-upmanship of a good round of Spy Vs Spy. At its worst, it's just another window into same shrill hectoring you find on a thousand forum pages, as the old arguments grind on interminably, and you start to question whether this is really much of a game at all.

Invented by blogging legend Justin Hall as part of a master's thesis, PMOG is a Firefox plug-in that turns the web into an MMORPG. You level up by visiting pages, using items to trap or reward other players, and completing user-generated ‘missions'. You can do as little or as much as you want: click on every mission, lay mines with bloody abandon, or just log in, surf, and let the process take care of itself. It's pointless, certainly, but then so is speed-running, and at least PMOG doesn't involve rote-learning Sonic the Hedgehog levels.

"We've been pleasantly surprised to see that passive gaming could be so popular," said Duncan Gough, PMOG's chief programmer, when we caught up with him last week. "I feel like we've learned a lot, and it's been exciting to be able to share our particular vision of games."

And nobody could say that vision isn't detailed. From the air-brushed steampunk artwork, to the clever reworking of videogame mechanics, PMOG has a very distinctive feel.

In short, if you like pop-ups, you're in for a real treat: once you've installed the game, almost every webpage you land on brings up a shower of notices about potential missions, the presence of in-game objects, and even updates on who has tripped or foiled your various traps.

Deeper in, the central mechanics revolve around data points. Earned by surfing the web, these allow you to both level up and buy items. Your item use and actions eventually dictate which of PMOG's associations you belong to - an inversion of the class system of most games, where you traditionally select how to play upfront and then try to stick with it. Associations limit the kind of items you can buy at the shop - if you're not a Bedouin, for example, you won't be able to buy more armour, so you'll have to find it elsewhere. As with so much else about the game, the system initially seems topsy-turvy and slightly pointless, but it's been fine-tuned to encourage trade and interaction between players.

Some items are tailored for attack and defence, such as mines, which cause other players to lose data points, or St Nicks, which make mines explode in the planter's face. Then there are more creative tools, such as lightposts, which allow you to link websites together to form missions.

Missions are by far the most personal, and hence most controversial, aspect of PMOG. The idea is to string together themed chains of websites, a kind of guided tour of your personal interests for other players to discover. They range greatly in quality, from a plod through the wikipedia pages of every shoe a certain player's owned since 1990, to the whimsical brilliance of someone else's five-stop guide to the best origami sites. People aren't backwards about telling you what they think of your work, either. Missions have a review system baked in, and it's rare that you'll find anything rated higher than two stars.