I fixed most of mine by adding a few fields in the Profile Field Setup. I added City, State ( as a dropdown menu and a zipcode. I got rid of 70% just from this. also, I have seen in my log files they are searching for
“yes i d like to create a new blog”
“registering for this site is easy just fill in the fields below and we ll get a new account set up for you in no time yes i d like to create a new blog”
“intext yes i d like to create a new blog blog with wordpress inurl register”
“i d like to create a new blog”
maybe someone can tell us where this text lives so we can remove these tags from the search engines. just by this they are able to see all wordpress sites. I tried it with google and it does work.