I think its important for the wallet to show how many wallets are mixing coins at the moment (live counter). Then we can also put a graph on some website that displays trend of this over time, which is a very clear indicator of adoption progress. Evan, can you implement this?
It will also help us who are willing to help the project to determine whether its needed to run liquidity providers at any given time.
I will also post this on dct
"How many wallets are mixing at the moment" is impossible to determine since each wallet has a multitude of addresses

But some version of this should be quite easy to do on one of the Block Explorer websites. Simply have a statistic section:
# coins mixed in last block
# coins mixed in last 10 blocks
# coins mixed in last 100 blocks
# coins mixed in last 1000 blocks
(Yes, this will double-count. E.g. if I had a 5-round mix going on within the last 100 blocks, my coins will be counted 5 times. Which is fine. The point is to provide some metric of mixing, not to be super precise with it.)