Sad to say but almost all famous CSGO betting has been banned by Valve.

Yes I was about to say I thought they stopped it. Heard about it awhile ago here on bitcointalk. I guess it got too big and steam didn't want to be affiliated with gambling.
That's not the end of CS:GO gambling though; there will always be some kind of illegal activity that will happen with the community. I'm a semi-professional CS:GO player, so I know lots of these things as I keep up with the community a lot. What happened was there was a lot of drama surrounding TmarTn, and all the Twitch broadcasters and how they had owned a gambling site(TmarTn) or rigged sites and asked for percentages ahead of time so they could win insane amounts of skins without much of a chance, and with almost 100% certainty.(Phantoml0rd and co). Phantoml0rd even made one of his Twitch moderators go in the pot, saying that they'd go in together, but somehow Phantoml0rd didn't go in, and the moderator lost a few thousands of dollars of skins. Phantoml0rd only repaid him a 300$ knife. Valve probably didn't want to get into all of this, so they just issued a notice for them to stop. Although it has been confirmed by people like Thorin(CS:GO caster for several major events and minor events) that it's indeed legit, many people (including me) have been confused by the wording and how it's pretty odd. Kinda weird for a legal document, yes? You can search more of this online if you want, but i'm just outlining this since I always post about CS:GO here.
Also note that sites like CSGOLounge are big parts of the CS:GO scene viewership; the viewership of the game is expected to decline as they are shutting down. CSGOLounge provides match betting with skins, and it's where all the famous matchfixing scandals happened(iBuyPower vs Netcodeguides). CSGOCrash and co. are still up, and they all insist that they will not cease operations and will conform with Valve's new rules, though I think they will still be shut down. I recently lost around 300$ on the site, I can confirm it is still up, even as of today.
Wow, that was a lot of typing and ninja editing! Quite an interesting read if you know where to look.
