The problem isn't the posts or threads column, it's your additional forum elements (ads, images, etc); v7.6.0 is totally mobile out of the box, it's 3rd party things that're added to it that need to be adjusted (have whomever is complaining load UBBCentral in their browser, they'll probably say it works out pretty good).

It looks like your navigation section and your ads need to flow with each other, versus trying to shove everything side by side (keep in mind, mobile browsers are tiny).

For you to go mobile you'll need to make sure that when you resize your browser that all elements resize with it.

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum, Scouters World
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
Longtime Supporter & Resident Post-A-Holic
VNC Web Services: Code Modifications, Upgrades, Styling, Coding Services, Disaster Recovery, and more!