Three questions please.
1) Is it possible to code adding and deleting from subscription for an email newsletter on a blog by working with a simple txt file located on a server containing list of email addresses by using php only?
2) How do I add first names there? A second list? Or email address and first name separated with a comma?
3) Can more users online add their email address to the file at the same time?
I am asking these questions, because I prefer not to study SQL.