nivosh wrote
the ability to write the users e-mail is very important, don't you think?
No, because:
a) sending bulk emails is out of the scope of a Wiki. It sends changes information if you subscribe to a namespace/page or it lets you send new passwords (if you're the admin)
b) DokuWiki supports all kinds of authentication backends, creating a general "interface" to all of them in order to send bulk emails is non-trivial
c) if it would be that important to a lot of people, somebody would have either written a patch, posted a feature request or written a plugin that does what you want in the past 5 or so years ;-)
so, there are multiple things you could do in order to maybe get what you want:
1. open a bounty at
http://dokuwiki.org/bounties and hope that someone takes it and implements it for you
2. submit a feature request at
http://bugs.dokuwiki.org and hope that the devs think about implementing it
3. hire a consultant from
http://wikimatrix.org/consultants that gets the job done
Hope that helps