Q&A sending visitors submitting questions to my main site's sign up form.

I guess I don't understand this plugin.

When someone goes to submit their question, they are sent to my network's main site/wp-signup.com which is also where my people sign up for sites.

So basically this plugin is worthless.

I would think they could sign up for an account with my individual site. NOT the network's main site's wordpress install.

They have the option to create a site while making a comment. This is ... ???

I must be missing a critical option to make them sign up for an subscription account to the subdomain's wordpress. Not the main website.

Example
http://msp.mainstreetagents.com/questions/

If you submit a comment you sign up here:
http://mainstreetagents.com/wp-signup.php

When domain mappin is on msp.mainstreetagents.com it's going to be suspicious to say the least to sign up at a diff site. Furthermore, that different site (mainstreetagents.com) has the sign up form merged with creating a new site (for agents). It's password protected.