Simple module, easy to install and can help some people to read your own language. It's use full if you do not want to translate all your products description.
It's important to write something good else the people will bannish your email. It's better to use in my opinion another tools like mailchimp than the internal newsletter
Do you know if there is a module to analyze the email is valid or not ?
Send an email and have some no valid email is no good for the server and it can be blacklisted.
The email system is not the best. Use something that is designed to send emails like mailchimp. All you have to do then is to figure out a way to sync the subscribers.
It may also save your site from being blacklisted.
Is it possible to use just one file and not to make for all pages ? Like I see inside the code, all products directory (new, specials ...) have their own files ?