What does ported barrel/slide mean?
 

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That's mean there are holes on barrel / slide so that the gun will cycle faster due to lighter weight.

So basically it increases fire rate, right?

you got it.

Wouldn't that be a disadvantage due to higher risk of something getting lodged there? XD

Usually, nothing gets stuck in the ports, save for dust - but a little cleaning can fix that.

Porting a slide/barrel also makes them lighter, allowing for faster cycling.

Real steel information straight from wiki:

Porting involves creating ports or holes that are precision-drilled into the forward part of the barrel (and slide on pistols). These holes are designed to divert a portion of the gases expelled prior to the departure of the bullet in the direction that reduces the tendency of the firearm to flip upwards. The concept applies Newton's third law: the exhaust directed upward causes a reciprocal force downward. Porting is most commonly used on shotguns, where recoil is most significant and makes rapid firing difficult. Even single shots of magnum-strength loads are uncomfortable for all but the most-seasoned shooters. Porting has obvious advantages for faster follow-up shots, especially for 3-round burst operation. However, in most instances porting does nothing to enhance the accuracy of follow-up shots.

So in a few words, faster cycling and lowers recoil? Huh. Kinky.

Thank you!

In real gun yes, lowers recoil much the same way compensator does by re-directing the exhaust to "push" the muzzle down. That portion is not used in airsoft unless you "port" the inner barrel as well. But it might lower "recoil" in airsoft simply due the the reduction in moving mass....

Ported slides means pretty much exactly as it sounds. Ports are machined in to the slide, essentially, to lighten the weight for faster cycling.
For example:

http://www.pbase.com/illusive_airsof...8/original.jpg

Generally, you will only find this on race / target / match pistols, because as mentioned, there is greater chance for dirt entry.

Ported barrels, for real world use, are generally aimed upwards, near the muzzle of the barrel. The purpose is twofold:

1. Blows off expanding gas behind the projectile so that as it leaves the muzzle, it will not be disrupted by gas expanding faster than the moving projectile. Essentially, it makes that individual shot more accurate. This does not apply to all ported barrel designs. Only some are designed for this.
2. Compensates for muzzle flip by blowing gas (energy) upwards. Essentially, it allows for faster follow up shots.

In airsoft, a ported outer barrel does nothing except look bad ass:

http://www.pbase.com/illusive_airsof...5/original.jpg

http://www.pbase.com/illusive_airsof...5/original.jpg

http://www.pbase.com/illusive_airsof...1/original.jpg http://www.pbase.com/illusive_airsof...5/original.jpg


The exception to that, is if the inner barrel is also ported, which aids in stabilizing the round as mentioned above, by reducing back pressure before the round leaves the muzzle. However, the inner barrel ports must also mate up with the outer barrel ports for this to be effective.