Once installed, there are only two fields to complete: your email list name and your API key which is supplied by GetResponse. That's all there is to it.
Then, fully expecting to see errors, I ran my test registration and I was blown away at how seamless this little baby works! I cannot say enough good about it - it just works and it did not interfere with my extended user registration form at all. This powerful little plugin opens our marketing possibilities to a whole new dimension. Well done!