[Suggestion] Ingame message boards or forum.
ANet would still not let that be used to sell things. They will not let players advertise for non-TP sales. They don’t want to be seen condoning it by not stopping it when they see it.
Dungeon run sellers are still allowed to use the LFG to sell spots in their group. They are doing content.
I would imagine LFG’s for various different SW and DryTop maps are fine. Some want to chest train, others want to reach the final boss level. LFG lets the two groups keep as separated as is possible. And it’s a large group of people doing content, using the LFG to help segregate the different groups of open world players.
Guilds have map chat and the forums. And they are displayed by people’s names so if someone sees someone with a guild that is a friend they can ask about their guild. Likewise if someone in a guild sees someone without a guild, they are free to ask them if they want to be in a guild. LFG is not the place to advertise a guild.