Excel - take two csv files and map them

You can use Query from Excel Files :

• Define name for primary table dataset - the short list of emails (Formulas tab -> Define name)
• Define name for secondary table dataset - the long list of emails with additional data
• Go to Data tab, select "From Other Sources", and from the dropdown, select "From Microsoft Query"
• Select your csv file and confirm that you want to merge the columns manually
• In the following window "Query from Excel Files", drag&drop the email column of first dataset into the email column of second dataset - a link between these columns will be created
• Go to File menu, click "Return Data to MS Office Excel", an Import Data dialog will pop up
• Select the sheet into which you would like the matched data to be imported
• Click OK -> you should see matched data with columns from both tables

Or if you don't mind uploading your files to an online service, you can use for example http://www.gridoc.com/join-tables and have the rows matched by creating a matching rule (Disclaimer: I am author of the tool).

Hope this helps.