I doubt you can actually set it in a thread title, since they are stored as in the database and not parsed by any sort of code. There are a number of ways that you may be able to do this, one option would be to:
Create the new thread with the content and title of whatever you would like. (Note: The thread title will be show to guests so make sure it is appropriate)
View the thread and make a note of the threadid it will be the number at the end of the showthread.php URL. (For example: https://vborg.vbsupport.ru/showthread.php?t=163489 it is the number in bold)
Go to the Plugin Manager in the AdminCP and create a new plugin for "threadbit_display" and use the following PHP code:
PHP Code:
if(intval($thread['threadid']) == 8 && $vbulletin->userinfo['userid']) { $thread['threadtitle'] = 'Hey '. $vbulletin->userinfo['username'] .'! Are you on the member map?'; }
Remember to change the number 8 to your threadid which you found in step 2
I'm not sure how this will affect performance though since you will be running this check quite often, I don't know if there is a more efficient way to do this.