I don't know why this is happening, but the TicketsNow ad that always seems to be served (to me, at least) in CommunityBuzz is forcing everything after it (the table containing all the thread titles) to be 480 px wide.
Code:
<!-- INSERT SPECIALIZED AD TAGS DEPENDING ON FORUM : START -->
<div align="center">
<!-- TicketsNow 468x60: forum(380), group(0) -->
<SCRIPT LANGUAGE="JavaScript" SRC="http://search.ticketsnow.com/interface.cfm?Kbid=2287&face=H">
</SCRIPT>
</div>
<!-- INSERT SPECIALIZED AD TAGS DEPENDING ON FORUM : STOP -->
I'm using Opera 9 on Windows XP; it seems to just be an Opera thing (sigh), because it renders fine in IE, Netscape and Firefox. Now someone's going to tell me to just switch browsers.