multi-address spam detector

I was doing a quick review of my Spam folder, which I do only rarely, as Gmail seems pretty good at removing only crud.

While running my eye down the list, I noticed two very similar emails.

Different sender names, slightly different text, but clearly the same spam.  These arrived at two different email addresses of mine.  I know email hosts can detect spam by seeing the same email sent to lots of different addresses.  Now I can, too.