You must have used BUZZ Feature of Yahoo Messenger during chat with your friends. It is usually used to get attention of the chat contact. When BUZZ Button is clicked, it generates a loud sound that attracts the attention of a person at once. Some people make BUZZ again and again that makes the chatter annoyed. I also use this trick while chatting with my friend when I see he is not paying notice to my messages.
Have you ever noticed how frequently you can use BUZZ option in your Yahoo chat window? Definitely you cannot use it more frequent than 7-8 second or may be more. But there is a trick that helps you to send BUZZ to your friend as frequent as you want, even per second.
<DING> is a secret code to send BUZZ without using BUZZ button.
Only you have to do is copy and paste this code <DING> in your chat window and send it as many times as you want. Getting BUZZ so many times makes a person really annoyed. Secondly, he pays attention to your messages immediately and in this way you catch the attention to proceed conversation.
In newer versions of Yahoo, you can also use up arrow button to send the previously sent message again. The <DING> is simple but create fun. Try it!