3. What happen if our mailing list is in excel format can we still use Dynamic Opt-in Emailer?

Yes you can definitely use the Dynamic Opt-in Emailer when the mailing list is in Excel format.

Dynamic Opt-in Emailer use mailing list in TXT format, an Excel mailing list can be converted into the TXT format very easily. Use the save as function to save the list as CSV file and choose comma delimited. This should save the list into a format which opt-in emailer can handle.

Tip: You can import your existing text based mailing list into the Excel for data manipulation purpose, then re save it as CSV format for use.