Originally, MeTal only knew about one timezone -- whatever one there was set on the server it was running on. Derp. But I think I've fixed that, by way of saving all dates in UTC format, and having blogs use a timezone setting for the sake of conversion.
I've since converted this blog over to UTC, and while there was a drift of a few minutes, I think that may have had more to do with the data I already had than the application itself; newly created blogs and blog entries don't exhibit any drift.
I might still have to do some work involving the way local time is reported by the client, but I think I can let that drift for now.