App for VB?
 

This is probably a dumb question, but given the inclination for younger folks to gravitate toward "Apps" vice browsers, does there exist an "App" that would work for VB 4.X?

For vBulletin 4, Tapatalk and Forumrunner (comes with vBulletin 4) are pretty much your only options as far as I know.
However, these are not standalone apps that are specifically made for your forum. They are apps that just plug into your forum through the plugin you install.

Correct me if I'm wrong, but doesn't Tapatalk require me to hose the forum on their server?

No, you install the Tapatalk plugin on your forum and signup on their site, then you're pretty much good to go.

And then Tapatalk users will bypass most of your custom code, and Tapatalk has access to your database. They win, you lose. :)

Sounds like one of this "thanks but no thanks" kind of deals. I protect (or try to) my users' data jealously. Maybe someday I'll take up app development and this will be my first app!