It would be neat to put some vertical markers on that graph denoting

1. When posts started costing sats (I think they were initially free)
2. When sybil fees were introduced
3. When posting costs jumped to 10 sats (this was a much bigger deal than people would expect)
4. When territories were introduced
5. When territories started setting their own fees (I don't think they could initially)
6. Million Sat Madness (area not line)