The incarnate system.
Killing any level 50+ badguy offers you the chance of dropping shards, provided you have done mender ramiel's arc in ouro for which you have to be level 50.
The lvl 50 TFs (ITF, LGTF, Kahn, Barracuda, STF, RSF, cathedral of pain) also drop components that you can take instead of merits, equivalent to 4 shards.
You use them to craft boosts detailed here
http://goingrogue.eu.cityofheroes.com/en-gb/game-info/incarnates/alpha-slot.html.
Alpha is just one of 10 slots coming over forthcoming issues.
You really need to be alpha slotted to do the 2 new TFs Apex and Tin mage (otherwise you get a -4 level shift meaning you're 46 fighting 54s)