Hi Anto,
The forums follow the
Time Zone you have set in your profile. When you log on, you'll see all dates and times -- message posting times, birthdays-- in reference to your profile's local time. When you're not logged on (i.e., you're browsing PK's forums as a guest), the dates and times revert to the default forum setting. I'm not sure what that is, but it's probably GMT.
~Pen
EDIT: This means that if you haven't changed the local time setting in your profile, it will follow the forum's default setting. Nitya's post below is further evidence that the default forum time is GMT.