Even tough i agree that steam users should use the official boards for their issues as well.
But since there are also "customers" on that forum I understand Larian could keep the reputation high and help there out if needed.
But hey they are probably busy anyway

Nice advice tough Wabewalker
Ok.
So Larian should also visit the xbox.com forums aswell then, as they have a large fanbase over there too.
What about every other gaming forum a fanbase develops?
It's not really practical when they don't even visit this forum enough.
You're completely missing the point.
Steam is the single biggest digital distribution network on the planet. People go their to spend their hard-earned money on games - and because many of their favorite games are linked to Steam, they naturally have a fierce loyalty to it.
The websites you've named are just a bunch of gaming websites. Those websites are just independent places where people go to rant or rave about games.
If you've spent literally hundreds of dollars at Steam, and have dozens of games linked to their site, then that site is going to take on a whole new meaning for you. Steam is like a virtual shelf that's filled with your favorite games. If you can't understand that this makes Steam different than an ordinary gaming website, such as TeamXbox, then I'd quite frankly advise you not to go into the gaming business.
Small developers who choose to ignore their own customers do so at their own peril. Sure, the giants like Infinity Ward can ignore their fan base and get away with it - small developers, on the other hand, need to develop loyal followings. I've spent some time at the Steam forums, and I can assure you from observation that the Steam members appreciate it when the developers stop by and take notice. (Visit the King Arthur forum at Steam, if you don't believe me.)
And quite frankly, I would argue that right now Steam is the only digital distribution network that the developers need to pay attention to. Even at a place like D2D (which is just as good as Steam) you don't see that loyal following. Steam is taking on steam, so to speak, and developers need to pay attention to it.
Sure, you can come into this thread and argue that the people at Steam need to register here instead. In my opinion, that's just dumb, because for a lot of Steam users that's just not going to happen. You have to cater to your customers, and learn about their likes and dislikes, whether you like it or not! Sorry, but that's how the world works.
I stand by my original suggestion. If Larian is smart, then they'll send somebody over to the Steam forum.