As of time of writing, it would be wrong to call this a proper replacement to other search engines - but it is a growing project, with ambition and passion, to provide a real alternative to ad-driven or subscription based access to the information on the web. Check them out, and if you have some passion to share for the project, sign up with an account there to help curate search results.

I use it as my "first stop" search engine, try to refine results when possible, and switch to another engine if there aren't any good results quite yet. Adding this to Firefox makes this process easy, and its helping a worthy, growing project.

No need. Just right click the address bar and click add "Mwmbl Search".