I think it is absolutely annoying especially since you can lose trust level 3 by not being on the forums for a few days…
so if you got trust level 3 once, you are pretty much are not allowed to go on vacation or something similar, because if you do, you lose it again and you have to start from the VERY beginning agian…
I did have trust level 3 once, I lost it, because I was away for a short amount of time… this is dumb…
It’s just Blizzards way of being obnoxious towards its players who want to post links or memes/gifs etc on the forums.
You literally have to do this to put a link in without level 3 which is stupid.
Either allow links or not, don’t force criteria onto the forum users in order to be able to do something simple you can do on a majority of forums online.
Hey can you explain to me my trust level i one day can post second day i can not.
So enjoy doing it there!
I love how it is now.
Blizzard no longer trusts me. I think it is because I look too pretty for them.
In more serious tone more annoying than gaining T3 is the mysterious unknown methods you can kiss it goodbye. Sod knows where mine went.
You need to keep up (grind, oh the irony) your trust level 
At least it’s not random.
Yet.
It kinda is though, some people have lost theirs and can’t get it back but others can and have so it seems RNG is active there too 
It’s also RNG as to whether you can post without a sub!
They are messing with us 
And not get bans.
If you get reported ingame or on the forums you lose the trust levels.
And as far as I am aware some sections are only available for ppl with a sub, while General is free for all.
the ingame one is if it actually goes through with a punishment,
and the forum one is 5 flags
When I’ve let my game time run out I’ve lost posting rights on general so I dunno it’s all confusing and doesn’t seem consistent at all.
Same with gaining TL3 back, people say they aren’t getting sanctions in game but still can’t earn it back but I have twice so who knows what’s going on.
I believe it’s a two-week span or something to actually loose it, so you losing it in a few days sound odd. I don’t frequent the forums daily and I still have my trust 3 that I got a few weeks back.
Twiluna already linked the sticky explaining it, but the tldr is read a lot of posts, like posts, post stuff and hope people toss a like (to your witcher) on the post.
As for in-game sanctions, if it was true there’d be so many less people who currently have trust 3, so it does seem odd that in-game correlates with forums even if it would also make sense due to the nature of the community and game.
The whole trust level system is a funky one, but it’s what we got so not much else we can do but provide feedback and pray that we can get a clear cut answer from blizzard staff.
Pachi kindly wrote a FAQ about how the new forums work with Discourse
https://eu.forums.blizzard.com/en/wow/t/the-ultimate-forum-guide-codes-trust-levels-faq
It explains trust levels. Trust levels are gained by meeting certain levels of activity and need to be maintained. If you aren’t active enough then your trust level can drop again or if you misbehave and receive a time out from the forums then your progress resets and you have to start over.
You can see what trust level you are by going to your forum profile and putting .json at the end. For example this is mine
https://eu.forums.blizzard.com/en/wow/u/punyelf-draenor.json
At level 2 you can post links from trusted sites such as Youtube for example. If you want to post a link from another site you can simply type in the url, highlight it and use the </> button and it will appear as my first json example above.
Well there’s your answer don’t let your game time run out.
You need to keep a daily activity, in order to keep your trust level.
While some things are quite easy like giving 30 likes in 100 days, others are not.
Like :
It’s a bit though to keep all of this tbh.
In example if you create too many unnecessary topics, people may report you for spamming.
Post something, that is considered rude and you can be reported.
Receiving 30 likes, in your posts, may be a little hard if you like to post some of your own personal thoughts.
I found that if you let your sub runs out, the system will automatically rule out your posts after a handful of days, not more than five.
I guess is a bit like flightpath.
Not for everyone.
Cheers.
Is what gets me, when you try to do it in 50 days xD
Best advice I can give you: maintain a daily activity.
On my case I enjoy forums so I logg in first thing in the morning.
It’s easier to find topics I enjoy replying, or getting ideas for topics.
I got to posts links without even trying to get there tbh.
I wish the game was that addictive tbh …
Cheers.
If I’m not playing I’m not paying 
sometimes it’s down to health issues that stop me playing and sometimes it’s just an oversight because blizzard is weird and does game time to the minute 
I did read of cases, where it was gone within days… I was away for 6 weeks though, still doesn’t change the fact, that this is indeed annoying…
Problem is we never know what of the requirements that causes us to lose the TL. I’m guessing its more likely the read 20.000 posts within the last 100(?) days ir something like that that falls off and not that ppl were away from forum for a day or two. But there’s no way to know and track your progress.