If it was a tables problem then vBulletin also couldn't display the data correctly. Here the problem is that vBulletin reads and displays the same data (vBulletin usernames and user titles for example) correctly and Classifieds do not. If I change the charset for that table to anything else, vBulletin will not work properly since the data in question is in the vBulletin tables. Both programs read the exact same data but only one of them displays it correctly.
My vBulletin is using utf8 format so it is irrelevant which language I am using. All unicode characters should work regardless of the fact which language I am writing in. A unicode character is the same in English as in any other language, that's the point of utf-8.
The main problem is that Classifieds are probably still using latin1 to read/write into the database like my quote in the previous post mentioned. That is why it can read the data that has been entered through Classifieds but not the data in vBulletin tables.
The problem begins when Classifieds need to read data that is really utf-8 format. Because it is reading using latin1, it shows question marks because it cannot interpet some characters.
Looking at the tables from vBulletin and Classifieds with HeidiSQL leads me to believe that the problem lies with how Classifieds write/read unicode characters. When I look at the vBulletin tables, unicode characters are displayed correctly so it seems both vBulletin and HeidiSQL understand the format.
Once again, the problem is that vBulletin usernames and user titles (or any kind of data extracted from vBulletin tables) are displayed incorrectly by Classifieds. Logic tells me that something with Classifieds is causing this since vBulletin has no problems with utf-8.