If you have questions about using mojoPortal, you can post them here.
You may want to first review our site administration documentation to see if your question is answered there.
Ok I set this to false
<add key="NotifyAdminsOnNewUserRegistration" value="false" />
and now everythink is ok.
The problem of the empty subject is caused by the fact that I didn't give a name to my site because it appears like text in the header, but I have the name in the logo so now there are two names (one in the logo image and one written on it). Must I modify it in the skin?
Yes, if you don't want to show a text title you can chop this out of your layout.master file:
<portal:SiteTitle id="SiteTitle" runat="server"></portal:SiteTitle>
Best,
Joe