I have installed and enabled the plugin and it doesn't seem to be working. I tested in the registration a blocked email address and a blocked username and it said both seem to be valid. Is there any documentation on installation or implementing with community builder etc.?

There is nothing to configure beyond the optional parameters - it works with Community Builder without changes - CB is installed on this site.

So long as the plugin is installed and enabled, it should be working. Do you have any other registration plugins or components installed?

The plugin is working - I was testing with community builder and the java script with them were saying the email and username was valid - it would be cool if you could get this plugin to intergrate with their register so it would show right on that page that they were invalid.

You mean CB is using Ajax? Didn't realise it did that, I will look into it and see what I can do. However, I may not be able to change the reports here, as it is difficult to override Ajax (which is what is proving difficult for JomSocial, though this is now almost complete).

Another point is that as only Spambots will usually be blocked, it isn't a huge issue if the Javascript reports as ok but the registration is the blocked. It should affect few legitimate sign-ups.