All I can do is repeat myself, in your case, you care how others are using your software, so you are building it for them and you want to make sure that they us

All I can do is repeat myself, in your case, you care how others are using your software, so you are building it for them and you want to make sure that they use it in the correct spirit. This is what the GPL is for. However due to the weird economy of software. Research costs are quite high. but manufacturing and distribution are about as close to zero as you can get. It is very possible to say "I built this for myself, but because it is easy to do, you can use it if you want". In this case you don't care about once it leaves your hands, once someone else gets it your part of the process is over. This is what the BSD style licenses are for.