I have email addresses in Column A & Column B and I'm trying to find matching
addresses between both columns. I have tried the following formulas however,
they are not counting the matching items correctly:
=ISNA(MATCH(B2,$A$2:$A4661,FALSE)) and I have tried this:
=SUMPRODUCT(($A$2:$A$662=A2)--($B$2:$B$662=B2))

What am I doing wrong?

Thanks for the help,