I've been looking for something like this for a while to provide copy / paste address book import functionality from Excel or any spreadsheet program. Google Apps script was interesting because you could do complex rules like adding validation but I don't think it's really designed to be dropped in to your site to be used by anonymous users and having Google Spreadsheets as a dependency isn't ideal.

However, for simple input this looks great. What else is out there? I saw the projects listed on this project's github but those weren't the same - just start editing and pasting.