Cheetah is a robot that messages the author if he finds the same content on other sites. You just need to message him that it is your content, not just something you have copied from other sites.
The site is still new, lot of work to be done but it's heading toward the right direction, a bit slowly though. But it will get better. I believe there is steemit faq that you could read on that could answer many of your questions. Here it is: https://steemit.com/faq.html