Solved a big problem for me, neatly and easily

My host was going to migrate my server because I was getting a lot spam caught in the “please moderate” emails from wordpress. Tech support suggested I install captcha, this plugin solved everything for me. I really like how you can selectively apply captcha, since I was really getting a lot of spam in comments, not in logins or other interactions, so I could selectively apply captcha. Very easy install, and now the many dozens (maybe hundreds) of spam emails daily has been reduced to zero.