The idea of the EGR is to recirculate some of the exhaust gases back into the inlet manifold to cut down on emissions when the engine is cold. The problem is that when the turbocharger gets a bit worn, it throws oil out into the compressor side and through the intercooler. It then meets the hot exhaust gases and gums up the inlet manifold.
You can blank off the recirculation pipe with a penny or buy a pukka EGR blanking kit.
The EGR is NOT for cutting down emissions when engine is cold.
The EGR mixes exhaustgasses into the inletmanifold at moments the driver does not ask lots of power. The less ideal mixture will cause the engines combustion to be less perfect, this will cause a less hot burning which means less NOx gasses in the emission. It allso has some effect on some particle emission.
The oily, gummy stuff coming out near the rubber hose of the actuator I've seen on mine too, geuss there is some leaking in the actuator, which might mean it does not funktion either