I have a large number os users who never posted on the forum, and when I send mass mail asking they why, most (majority) reply asking for his/her username and password because they forgot it.
There is any why I could send mass mail using doemailusers.php and then including the username (and even password) inside the e-mail like :
"dear user [name] ,
Your username is [username]
and your password is : [password]"
??
would be great if we could do it. Inserting variables inside the mass mail.
Is that possible?

I don't think I would do that- I had a user with the email of [][email protected][/] and he hadnt used that email in about 3 years. One day it happened to sign on in my contact list for Trillian and I met a lovely woman named Pam in Iowa whom the email had been re-assigned to. Pretty weird

The password is stored in an one way encrypted way in the database, thus you can not send them their password.

OK. I would not send the password...
but my question still: can I send the username at least?

Can I include any info from the database inside the mass mail program?
That would be great if I can

well you could rewrite it a bit and send it yes.

If you wanted to send a password - there is nothing to stop you from sending a temporary one. Would need a big of jigging but it should work.

If they get the email, all they have to do is enter their email into the forgot password field on the login screen, then they get botht a Username and a temporary password sent to their email address.