Any details on how this edge works? It's moderately expensive, but seems cool.

1) Is the impact significant? (hard to say, yes)
2) How is it judged that others of your faith are there? Do non-priests have coded faiths? Does it only count empowerment/tattoo'd players?

Thanks!

The edge increases the level of communes when you are in the presence of people who are in your religion, which is based on your "god name", which is what you sometimes see when you commune things.

For example:
You feel a surge of holy power as Darth Sidious heals your wounds!

Characters with "custom" empowerment or whose patron Immortal uses inconsistent "god names" probably should not take this edge.

Personally, I probably wouldn't invest in this edge unless I were playing a very popular religion during some serious bandwagoning.