I have a website that provides a free tool for a casual user. But if someone wants to do something special with it, like integrating it into their own website or do something creative of their choice, they have to buy a license. It’s not very expensive.
Recently, I have seen some IP address accessing my script a lot. After a bit of research, I managed to find out which website that ip address belongs to. That person has a decent website that might be making decent amount of money each month. Yet, rather than licensing my script and implement it locally, that person chose to bombard my website with thousands of requests per month. I analyzed my last few months of logs and gathered a handful of ip addresses that were abusing my free script and blocked them. I know I can use a captcha and reduce this type of abuse, but I will probably track ip addresses and block a request if there were too many requests from that ip in the last 1 hr. Of course, I need to be careful about not blacklisting search engines. I don’t want the genuine users to go through the captcha system, so that’s why the idea of ip address based logic.
In general, I think, there are people out there who are ready to abuse a system rather than spend little money and have a much better solution.