Yes and that is what people are doing with steemit. Just look at all the tools people are making to enhance steemit and adding value to it.

Also creating something that enhancing another company's product it is best to do it and have it done or else what happened to you happens all the time. There is no way to prove that you had the idea first. They could just say they were working on it for a long time before you. I did a post on this saying "Entrepreneurs don't ask permission". A leader doesn't ask someone else if they can do something. Just to be clear though I'm not talking about doing anything illegal. I'm talking about adding value to a product, a service or creating something new.