You can do HTML tags in some places, but you are not supposed to. Vadi used to do it with Glomdoring's news posts, but the Administration put in a change to prevent that (specifically written as "Glomdoring's news posts were not intended to be so colourful").
I issued myself for clarification, the official word -
Sent By: Oneiroi on 06/15/4:38
Greetings.
In answer to Issue 1412, it is never permissable to use things such as
HTML to change the colours of letters or other in-game text as we
consider that extremely OOC. The only colourisation in letters should
be from bookbinding stamps and no other source. Thank you.
Everiine said: The reason population is low isn't because there are too many orgs. It's because so many facets of the game are outright broken and protected by those who benefit from it being that way. An overabundance of gimmicks (including game-breaking ones), artifacts that destroy any concept of balance, blatant pay-to-win features, and an obsession with convenience that makes few things actually worthwhile all contribute to the game's sad decline.
There's a perfectly reasonable reason why HTML-code is banned: Not all clients parse it. So for those not using those clients, well... it'd just look darn ugly.
Answers
Alas, this thread may fix that oversight.