Adding reCaptcha to your forms
Create a reCaptcha key
Add the key to Contact Form 7
Contact > Integration > reCaptcha
Add reCaptcha to each of your forms
Add this within the form field defines (e.g. just before your submit button)
[recaptcha]You should know
Using googles reCaptcha adds a call to their javascript with your unique key to every page load of your web site. So the trade off for using reCaptcha is that your site informs google of every new user that visits your site, regardless of whether they use your forms
Feel free to comment if you can add help to this page or point out issues and solutions you have found. I do not provide support on this site, if you need help with a problem head over to stack overflow.