@marcelmaatkamp did a good experimentation. Having such scripts in place could make steemit only better. I also did a proposal, rather a simple one that should ensure you need to read the content in order to be able to comment. It's plain and stupid, but sometimes stupid solutions works best. Anyhow let's see the opinions.
https://steemit.com/steemit/@crt/what-steemit-really-need-is-a-captcha