I've always been in favour of having local support for time zones.
If that is not possible, it should at a minimum be set to an international standard, like GMT. At least then I'd know to add 1 hour, instead of trying to figure out what time I'm looking at, whether or not its set to a local summer time or not...
Would it be simpler to replace the time with a 'Posted 5 mins ago'? That would be more useful