Second that what was said by @goinmerry, was on my mind actually when reading your post. There are a few groups where you would find a few constructive discussion. It's true sometimes scammers have been trying to post a few scam sites like Ponzi or whatever, but due to strong moderation, they fail to do that. Everyone knows Telegram has become a safe haven for scammers due to anonymous and encrypted communications. It's become easier to scam peoples and scammers getting advantage of that anonymity. Most spammers always add you to a new group unless you turn it off from privacy settings. So, be careful when you are in a telegram, you may follow a few reputed exchange or news source. But make sure you are not doing any financial deal there.