I wish to add a little field to my website to let people enter their email address.
Should I send that email to the boss, and he will add it to a manual mailing list (outlook or anything else)
or
add that email to a database or flatfile and have a little online management system to send those newsletter directly
Better: free
What is YOUR solution ?
take a look at phplist
its a open source newsletter management system
There are many mailing list solutions out there - google is your friend.
It should be relatively straightforward to write some code that links the front of your website with the mailing list backend, and many solutions will assist you in this process. I think I'd advise you invest some time in setting up an automated solution rather than handling the continual, linear burden of manually managing the list.
A couple of examples of completely differing management tools, one open source, one commercial:
There are lots of email list packages out there. Personally, I am happy with minimalist.
But no matter what solution you are going to choose, you should first of all think about legal consequences. Consider the legal restrictions in your country and think about malicious folks that paste somebody else's email address into your input box.