Allow optional location identifiers for each match
First off, I use Challonge to run dart tournaments... where we have generally some number of boards (often numbered 1 to 4, or 1 to 6, or similar).
Each match should allow you to add a "board number" or some other location identifier to it, and notify players what board number (location) they are called on when the match is started.
Additionally, if you can configure the "max" board numbers (locations), it would be nice for the coordinator to be able to quickly determine which boards are open, and which matches should be on which boards (which helps with the "what board am I on" question all night long).
This would make this more of a "slam dunk" for me to use and subscribe to... that, and well... allowing "singles" or "doubles" for the signups.