What Iphone editing app do these people use?

Http://web.stagram.com/p/267322495533164321_23533688

http://web.stagram.com/p/267247881017109390_10790009

I think they're cross-processing effects. When someone shoot film, they have the option of shooting with slide or negative film. Developing slide takes different chemicals than developing negative, and cross-processing involves using negative chemicals on slide film or vice versa. Basically, all it does is make the colors a little different, and sometimes a lot more vibrant.