[Off-topic] Axis_Drummer:
Portals

The makers of the game have populated the earth with a large number of “Portals”, visible to those using the game software. They are colored green, blue, or grey, depending on whether they are controlled by the Enlightened, Resistance, or are uncontrolled. They are often associated with landmarks such as public sculptures, libraries, and notable buildings. The density of portals is typically highest in densely-populated regions, especially the central parts of large cities.

Each portal may be equipped with up to eight Resonators and four Mods. An unclaimed portal has no resonators. To claim a portal for a faction, a player deploys a resonator on it.

Players may submit requests for the creation of new portals.

Resonators

A portal may be equipped with up to eight resonators, which must all be from the same faction, which is considered to own the portal. Resonators have levels, ranging from L1 to at least L8. A player can deploy resonators only up to their own level, and there are rules about how many of each level they can deploy.[4],[5]

A portal also has a level, which is a function of the levels of the resonators with which it’s equipped. For example, if all eight are L2, then the portal is also L2. However, a portal with 3 L1’s, 1 L2, and 4 L3’s would also be L2. The level of a portal controls the level of the items that may be obtained by hacking it, its resistance to attacks, and the maximum distance of links that can be constructed between it and other portals. The rules limiting the number of high-level resonators a player can deploy have the effect that players working together can create a higher-level portal than any one can individually.

Resonators, when deployed, are fully charged. The charge level decays spontaneously over time; when it reaches zero, the resonator is destroyed. Players may recharge resonators. This may also be done remotely, if the player is in possession of the respective portal's key. The effectiveness of a remote recharge depends on the player's distance from the portal.

Mods

A portal may be equipped with up to four Mods. In late 2012, the only Mods available are Shields, which increase the portal’s resistance to attacks.

Exotic Matter (XM)

Many interactions with portals require the use of XM; the mobile client has a continuous display of the player’s XM reserves. XM is scattered across the map of the world, represented in the mobile client by small bright glowing drifting blobs. If a player’s XM reserves are not full, any XM that comes within the player’s perimeter of interaction is sucked in and added to the reserves. XM is found sparsely on the map, except near portals, where it clusters densely.

Attacking a portal

To attack a portal owned by the opposing faction, a player deploys an Xmp Burster, using the mobile client. Xmp bursters have levels; a player may deploy a burster up to their own level. The success of the attack depends on the relative levels of the Xmp burster and the resonators, whether or not the portal is equipped with shields, and the physical location of the attacker relative to the resonators. Successful attacks reduce the charge levels of the resonators; when they are reduced to zero, the resonator is destroyed. When all eight resonators are destroyed, the portal turns grey, and the attacker may claim it for their faction by deploying resonators.

A portal which is under attack may in turn attack the attacking player; this depletes the player’s XM reserves.

A player may defend a portal that is under attack by recharging resonators and deploying replacements for destroyed resonators. Recharging a portal may be done using the mobile client for any portal for which the player has a key, even if the player is not near the portal at the time.

Linking

A player within the interaction range of a portal may link it to another portal, if the player has a portal key for the destination, if the link would not intersect an existing link, and if the other portal is within the first portal’s linking range, which depends on its level. When three portals are linked in a triangle, this creates a Control Field within the triangle. The space occupied by the field is claimed for the player’s faction, which is rewarded with a number of Mind Units depending on the population density and size.

Leveling

Players begin at Level 1 and progress through levels by accumulating Action Points (AP); the highest known level is L8. Players receive AP for hacking opposing portals, destroying resonators, deploying resonators (with extra points for claiming a portal with the first resonator, and completing its complement with the eighth), breaking links, making links, and breaking and creating control fields.

Passcodes

One or more times every day, media objects are posted to the Niantic Project Web site, which contain puzzles of various forms. Solving the puzzle yields a Passcode, a short sequence of letters and numbers, for example “ezekiel27w”, which may be entered into the client software to receive bonus XM and AP.

Info from: http://en.wikipedia.org/wiki/Ingress_(game)