This hack will enable you to DISABLE SHOWTHREAD according to USERGROUP. This will allow all your members to view titles and topic counts found within a section. Think of it as "window shopping". Your members will be able to read all topics from the forumdisplay.php page but, will not be allowed to read it's content.
Viewable in index.php

Viewable in forumdisplay.php

Access granted to read showthread
Access NOT granted to read showthread
The edits below will prevent anyone from viewing the contents of a post from
within showthread, printthread, showpost, and archives.
// ================================================= \\
// == Copyright © 2004, GO-TOTAL, LLC for vBulletin
// == vbulletin Copyright © 2000 - 2003, Jelsoft Enterprises Ltd.
// == This file may not be redistributed in whole or significant part.
// == Visit http://www.gtwebhost.com and
check the power of GTPUBLISH
// == HINT: Click the Style Changer located at the bottom
// == Please donate if you find this hack useful: Donate to GO-TOTAL LLC
// ================================================= \\
This feature can be used on a per USERGROUP and /or per FORUM basis. You, as the admin, will have complete control.
You will need to modify:
And, add 1 new phrase to Permissions.