The existing plugin list typically list the author name with a link to their homepage for each plugin. One method would be for someone to scrape and cache th

The existing plugin list typically list the author name with a link to their homepage for each plugin. One method would be for someone to scrape and cache the existing plugin list along with each known plugin author's contact/home page information. When authors sign up for an account on the new site: have the signup process provide the user a "hash code" to insert anywhere they want into the HTML code or as a HTML comment or header on their homepage to confirm author access to the plugin page on the new site.