Hey Christoph,
I have the same dilemma, the emails are consistently being downloaded to my phone at a rate sometimes in the 50 - 60 per day.
There is a couple of solutions that I can think of ...
1. Leave the forum (which I still dont want to do even though there is very little activity)
2. Get Admin Dude to take away your moderator rights.
3. Consign everything which comes from lightart to spam ... you will miss private message email alerts or general emails sent by admin but then at least they would not be coming into your inbox.
Hope that these suggestions help ... I am going to consign everything to spam as you will get any private messages when you come online to the forum anyway.
That's what I've done Tim, they go to junk mail. I check it daily anyway before I consign them to the trash.