How about opt-out instead. A button to disable it on a domain. Its very non-intrusive otherwise but I'd still like the option to disable thing. (I also sent this suggestion as a note from the bottom of the extension)
As I said in email, you only see the sidebar two times per domain (unless there are mentions of the particular URL you are on, then two times on that URL). You can also disable ampie on a domain completely by going into settings: click on the ampie icon in the extension toolbar, and you can add blocked domains there. URLs from those domains won't get sent to the server to be checked, and the sidebar won't pop up.
Thanks for building Ampie!