Pretty good Rated 4 out of 5 stars

For you people getting duplicates:

Open up Microsoft Excel.
Paste your entire list into Column A.
Sort the entire column alphabetically (A > Z). This is very important.
Click on and highlight Column B.


With Column B highlighted (press the gray B button above the column to highlight the entire column), enter the following into the “formula” box in Excel.

=IF(TRIM(A1)=TRIM(A2),”",TRIM(A1))

After the formula is filled in, and with the entire Column B still selected, go to the menu in Excel, and choose: Edit > Fill > Down.
This will fill Column B with a new, updated list, with all duplicates removed.
Now, you’ll want to copy that column into a new spreadsheet. “Copy & Paste” won’t work…
Select Column B, and choose Edit > Copy.
Create a new spreadsheet, and select Edit > Paste Special > “Values”.
Now you should have the final, updated list. You can sort it now, and remove blank lines.

This review is for a previous version of the add-on (1.1.1-signed). 

Hello FlavourD

That's a GREAT tip for the users. Thanks a lot

We'll try to add this duplicate email removal in the future releases as well.

Thanks again :-)