
You might or might not have heard of Ingress. Certainly, not too many people outside of the Android owners have, and not a significant percentage of those have either.
So, what is it? It is a multi player game from Google, with a two faction, 'capture the flag' like gameplay, in a huge, persistent world. So far this description is very typical for MMOs, so why would some people this it is not one? For one single reason: your in-game location is tightly bound to your real world location, thus your gaming experience is very different from an average MMO game.
Well, I do think it is a fairly common MMO, with almost all the common trappings: Collecting experience and gaining levels; building an inventory; working in teams for a common goal; grinding. Yet, there are a few very interesting design aspects which makes it special.
The most important one is the one I mentioned above already: You need to physically move to different locations in the real world for to be able to get close to important points - the portals. As these portals are not equally distributed over the surface of the planet, you might find that the are where you live/work/travel/etc has a lot/just a few/none at all. This will obviously affect your game a lot, as the portals are the main source of your items. Consider the difference between the case when you have a home portal (community term for a portal that you can reach from inside your flat) and the case when you only see portals if you go to the closest town, and only a few even then. It also changes a few things about your habits: You start choosing places for going out where there are portals, and you may even start referring the portals as actual real life points of interests - I often tell my wife to meet at 'The Insect' or other portals close to our flat.
Also, I admire the way how the game motivates you to join your local community and play in groups. There is a very simple motivational factor: Items for a given level can be gathered mainly from the same level portals, so say level 6 items are mainly looted from level 6 portals. Yet from level 2 (maximum level atm is 8) the players are only able to create portals which are lower level than their own. For up to lvl 4 this is acceptable, but then it gets gradually worse, until the point when a level 8 player is only able to create a lvl 5 portal on his own. As a result of this, players start to actively look for communities when they reach level 5-6, and at level 8 (where you need exactly 8 players to create a lvl 8 portal), they often organise events which are very similar to raids in normal MMOs. The main difference here is obviously the requirement to turn up physically. :)
Another point to mention is the simplicity of the level/item system. Atm there are 6 types of items in the game: Resonators, Bursters, Power Cubes, Shields, Keys and Media. Of these, the first 3 are levelled items: They have versions between lvl 1 and lvl 8, and you can only use them up to your own level. Shields have 3 different kinds, but you are free to use any of them on any level. Keys and Media doesn't have level differences (Media items have levels, but it doesn't mean anything). It is very simple to understand which one you can use for what, but it offers enough variance that you have a yay! moment from time to time when you get a great loot from a hack.
It will be interesting when - probably next year - Google will port the game to the iphone. A surge of new players, and the inescapable chaos will give the game a new kick, I am sure. :)