In reply to Neo.

Joost, vulture? I think this is not your paid promotion or your site. As you mentioned you want to provide a free plugin for almost everyone (except those who you fire as customers ;)).
Tony provide the same. What is wrong if he offers an own solution if he thinks it's better than yours?
This is not competition, I hope cooperation. You helped him with security issue, he can help you with huge support requests, that he can take some users for his plugin :)
Users who use your plugin don’t belong to you, you uploaded and manage open source code to free WP directory, as Tony.
I believe that anybody can jump into any discussion about your plugin and offer different solution/plugin/code/service for SEO.