You don't get sg from talking in the forums, you do get xp from and by levelling trough that way you can get some sg for each level
The maximum level is 30, you can see levels here. https://gamehag.com/ranks
As for the rewards from leveling up, I actually don't know. I've seen someone say they got 15 SG from reaching lvl 3.
in 3 steps
Choose the game that interests you and play itfor free.
Every game has some quests for which you will receive Soul Gems.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
You know that on Gamehag you can get real rewards for free, right? Join us, complete walkthrough and get your chest!
I know you are getting XP by talkong in forums, and that after 3 lvl you are start to recieving SG's. I want to know how much you're getting it and what is max lvl.