Suggested actions to curb RMT advertising and make their operation more expensive in order to raise the cost of gil which in turn reduces the number of buyers;

Blacklist entries are account not character based.
Automared 'Report as spam' option in right click popup menu when right clicking names in chat log.
Report as spam also automatically adds the reported player to your blacklist.
Better filtering of tells & better chat filters in general.
Option to suppress tells from people not in the same LS, FC or on a player's friend list.
Harsher penalties for buyers.
Add a 5 second delay between tells (this forum uses better flood control).
Cap the number of tells per day (restrictions on posting at this forum are aimed at reducing abuse by restricting post numbers based on character level).
Attack the prices of commodities RMT sell to generate the gil they use by introducing the sale of items such as shards via NPC to force a floor value on commoditues - this would increase the time taken to generate gil for resale, thus making gil more expensive and players less likely to buy gil.

Any other suggestions?