Currently we receive email notifications if we're the author of the question, but not if we reply to the question or if we're simply interested in it. I use the RSS feed to get updated on new questions and there are a bunch I'd like to see an answer for, but there is currently no way to do this without bookmarking all the links and visiting them periodically to see if any updates have been posted, which is incredibly inefficient. Please consider adding a "subscribe to this topic" option that sends us an email when the topic is updated.