It will depend upon what email client you are using. We have worked out how to sync email responses into IS from Office365/Outlook for example. I’m fairly certain that a similar approach would work with GMail as well. Other email clients might have different details to work out but I imagine it would be possible with most. The new IS UI has a plugin for gmail but the current UI needs a different solution to sync email responses on existing contact within IS. So it’s not the simplest answer but the end game is that while many have not been done, there shouldn’t be any that can’t be done.