Instant Message

YaBB is about community and communication. And there are plenty of ways to communicate: Posting on the boards, Instant Messaging, E-mail, ICQ, AIM and YIM. Of course, all methods of communication are only available to members. An exception is when the Forum Staff decides to allow guests to post on the boards: in this case all unregistered users are NOT allowed to do is viewing the Member List and sending Personal Messages to members. 

Instant Messaging

While e-mail is a good way to correspond privately with members, it has several drawbacks: You must open your e-mail application to write and send the message; the recipient must open his/her e-mail application; check his/her mail and your message will mixed in with all the other mail and it can take sometimes several minutes to an hour for mail to reach the recipient. 
As an alternative to e-mail, YaBB offers a faster, more private method. Instant Messaging on the boards provides instantaneous delivery to the recipient's Private Mailbox. The mail is sent and received entirely through YaBB, so neither you nor the recipient have to open another program or leave YaBB. Instant Messaging also gives both the sender and recipient greater privacy: No one's real e-mail address is revealed. Instant Messages show only the handle and name of both parties. 
If a recipient isn't online, Instan Messages wait in the member's IM box until the next time s/he logs in and manually reads and/or deletes them. YaBB Instant Messages is a self-contained, highly private e-mail system. 

Deleting Old Messages
Delete your "old" instant messages by :
There is a BIG delete button on the top of the "list" Of IM's just click on that then it will ask you if you want all deleted, click yes... should get em all! To delet individual IM. click on the delete next to the ones you want deleted.