What threads are you referring to? In most of the forums, they're locked for being off topic. In FS/FT, they're locked for excessive bumping or a problem with the user (dealers, ripping people off in the past, etc). In Hot Deals, non deals and attempts to defraud companies are locked. In OT, pointless, vulgar, and/or repetitive threads are locked. If any of those reasons don't apply, the mod is having a bad day.