<p>You will receive a notification only if someone answers your comment by using a <a href="http://meta.stackexchange.com/questions/43019/how-do-comment-replies-work"><code>@yourname</code> comment reply</a>.</p>

<p>Not everyone uses it though, so I suggest you use it even when you don't need it. For example, even if you know the person who posted the answer you comment on will get notified, use the <code>@hisname</code> when you write your comment, to suggest it's the way he got notified, so he will use it too (not needed with a regular user though, but it can help with new ones).</p>