This is a low priority request. I just wanted to write it here while I'm thinking about it. I have an install of b2evolution with users and blogs spanning several time zones. It would be nice for each blog to be able to set the offset from the server time independently.
Good request, IMHO, because I've just added a TODO about having finer granularity with the time offset. It should get stored as seconds internally to allow an offset of 0.5 hours and such.
However, the time difference gets used as a server system time difference - not per blog.
IMHO, additionally to the global, server's time offset there should be a timezone setting for the user. This would allow to display times in the user's format, regardless of which blog he sees or which stats he looks at.