This will prevent Adrian from sending you messages, friend request or from viewing your profile. They will not be notified. Comments on discussion boards from them will be hidden by default.
That said, be your best self—the self who follows reasonable gaming and social etiquette (as we’ve covered so far), is thoughtful and considerate of others, and is genial and positive enough for people to want to be around.
I think this is the best advice that could be said in this book, honestly.