If you hover over your mini-map a box appears that has two check boxes. If you select them then you get two permanent progress bars fixed to the top of the mini-map box.
These bars show how much of the map wide meta-event has been completed and basically how much reward you will get at the end.
Doing events increases your personal bar and that scales to 200%. This is actually then saved per overflow of the map. So if you disconnect mid-fight, and reconnect, you will notice your personal progress remains the same as long as you mapped into the same instance, allowing you to receive your rewards. You also then receive the subsequent tier rewards as indicated by the white dots on the map-wide meta bar. Also, participation does not reset when the map-wide meta resets, meaning if you stay on the same map, you will continue to receive occasional rewards even though you are not doing any events.