How to write timezone friendly django application using MySQL

The basic steps for this are: store everything in UTC, do all arithmetic in UTC, store user's timezone info and convert to that at the last second. Python does not have built-in TZ information so you need pytz installed.

We do it without storing a user's time zone via jQuery and a custom script that converts all UTC time stamps on a page to the local time setting of their computer. This works well for us because we have travelers who use the service through a variety of time zones.

The second touch point is our iPhone app, and the SDK has built-in support for converting UTC to the client time.

"UTC used to be called GMT."

Not exactly. iirc UTC is based on atomic clocks while GMT is based on astronomy. The whole time measurement system is quite complex and messy.

But in most cases it probably is fair to call UTC and GMT equivalent.