I met someone recently who seemed to share some of my technical interests and we started discussing doing some work together. However, after emailing back and forth a few times they added me to their email blast, which updates their "fans" on all their projects and events, without asking my permission. This is a source of concern to me. If they do this to me, they may well do it to anyone I happen to introduce them to. I would like somehow to politely let them to know that they should at least ask permission before they do this.
Just a firm polite email, that says thanks for considering you for inclusion on the list, but could he please remove you. I think that's better than filtering his mails as it gives him the hint that he shouldn't automatically do this. I wouldn't worry about introducing him to others, it's unlikely they'll judge you for that
If you don't mind straining your relationship with this person, go to him and tell him flat out that you already are receiving too many email messages and if he could take you out of this distribution list. What happens to others is their own issue, not yours. You are not the email etiquette police in the office or in his circle of friends. So, stay out of making generalized statements.
If you somehow value this relationship and do not put a strain on it, just create a email filtering rule (any modern email client have these filtering rules) and put whatever comes from this person, (probably with a certain keyword in it) into a read-later folder or directly into trash. If you are filing them somewhere, and if he asks you something about the content of one of his golden pieces, you can tell him that you did not time to read it yet but will give your feedback after doing so, and go to your email archives and read it, if it is an important matter. Or you can say something like "hey, you know I gets tons of email everyday and in order not to lose it, I created this filter, it automatically files your messages in a folder for later reading", which in my opinion means "what you are sending me is garbage but due to my relationship with you, I do not have the heart to tell you that, they are garbage"
Make a polite request and ask them to please remove you from their email list. You could even say something along the lines of I took a look at the first couple emails, and I certainly appreciate you thinking of me, but that is not something I am interested in. Would you please remove my email from this list? Thanks!
As for people you introduce to this individual, don't be afraid to take them aside privately and advise them about the email list. Pass along the same advice to politely ask to be excluded if indeed they find themselves added to the list. It could turn out that the person added you to the list simply because of the shared interests and was acting in what they thought was in your best interests (and not merely spamming).
If all else fails, you can still filter these emails straight to archive or trash, and no harm is done to you or them.