I’m in a similar situation and hadn’t thought of it that way. My take on the email I receive is that they fall into one of these categories: a) genuinely intended for me (and not spam), b) spam, c) genuinely intended case of mistaken address (they forgot to include another character), d) someone using mine as their throwaway (site sending verification email), and e) someone using mine as their throwaway (no verification process, ergo not altogether different from spam).