"X User Has Quoted Your Post"
Everyone I make a post in a thread, and later when the thread gets more replies, I have no idea if any has quoted my post. Instead, I have to look in the thread again and find my post, then scroll through the comments if anybody has quoted my post and see if anybody responded to what I had to say.
Solution: Say you posted your comment in a thread, and someone has quoted you. You don't know who, you don't know when, and you don't know which page someone quoted you in. Now you get a message in your inbox with the subject titled "X User Name has quoted your post".
On the message in your inbox, you will see your quoted post, along with the person's post that quoted you. You will also receive the link to the thread with the post that quoted you there in the exact thread and it's exact page.
That way, you don't have to scroll through page by page and comment by comment if anybody has quoted your post. Its also great how you know right away the second someone quotes your post, you get the message in your inbox.
Thoughts? I'll explain more if I need to clarify a bit.