The Post Thank Hack for vBulletin is pretty awesome. I have my forum setup so that each Thanks equals 1 rep point. Previously I used Paul M's unread posts and reputation mod to show new rep notices which alerted members to thanked posts. Starting with 4.2, reputation display is included by default. For one reason or another, thanked posts do not trigger the new reputation notice. Enter the Recent Thanks mod which works great. It adds a page called recent thanks that lists all recent thanks as well as alerts users to new Thanks in the notifications menu.