Hi Peter, Thank you for raising this issue - it is an annoying distraction. The general standard of the list is very high as one would expect and it is a shame to see this kind of behaviour polluting the discussions. I am very happy to have to earn a privilege to post and am happy for anything I post to be moderated. I would welcome any proposition to keep spammers off the list whilst keeping it open but I don't think any solution should impose additional burdens on the moderators. I think that this warrants a bit of thought and will give this some consideration. Your proposal sounds good and I support it. In the meantime thank you and many thanks to all the team who make this happen. I find the work on seL4 very valuable and relevant. best regards to all, David