Since Chénier was interested and I have the data anyway. These are the average amount of message sent per realm over the last 4 weeks (numbers are per week).
EC
- Perdan (52.75) / 12 nobles = 4.40
- Sirion (554.75) / 43 = 12.90
- Caligus (97.25) / 13 = 7.48
- OI (4.5) / 5 = 0.9
- Nivemus (196.75) / 15 = 13.12
- Eponllyn (42.5) / 12 = 3.54
- Fallangard (13) / 7 = 1.86
- Perleone (83.25) / 5 = 16.65
- Vix Tiramora (294.75) / 19 = 15.51
- Alara (72.75) / 13 = 5.60
- Minas Nova (11.5) / 7 = 1.64
- Shadowdale (55.75) / 10= 5.58
- Highmarch (424.25) / 33 = 12.86
Average letters per noble per week. To keep in mind that noble counts have changed some since the first data was taken, as Highmarch at least gained a few nobles from elsewhere.
Still, a pretty strong grouping of realms with less than 2 letters per noble per week and realms with more than 12.