This happened to me a year or so ago, I stopped getting emails telling me when people had replied. I tried loads of settings in hotmail thinking it was maybe some spam filter or something but in the end I changed the email address on my account and it's worked since.
I have the answer - we currently stop sending all emails to you, if you report even just one as spam. We don't differentiate currently between the transactional emails eg. thread/post updates and the promotional ones eg. partner emails/newsletters etcs. Looks like you reported an email as spam from your hotmail account back in August last year, so the system automatically stopped sending you emails. We're going to separate out the transactional and promotional emails then clear the block list from the transactionals as members should always receive these unless they suspend their membership. So there's no need to change your email address we'll sort it all out on our end.