Some ponzi are advertising as cloud mining, so please beaware.
But there are lot of true cloud mining services available for us to get benefits with them. But, we need to be more careful to determine the legibility of a services before getting starting with them. I just see a service discussion topic how to check a cloud mining is real or not. It would be safe to follow them.
The only real cloud mining I've heard were Hashnest and that's it
Hashnest is a trustworthy company and I already put few GH/s there so I can confirm that
Besides, They were the one who made Antminer
Besides, most of the cloud mining are safe at first because they are still baiting for more users to come in, when they have enough they just need to act like they've been DDoSed or Hacked
It happens to most of the Cloud Mining