What’s the point of using wordy Time Zones?

I know this isn’t specific to PHP, but what’s the point of using timezones listed like this :http://us2.php.net/manual/en/timezones.america.php? For example “America/Indianapolis” and “America/New_York”. What is the problem with EST, EDT, CST, CDT, &c?

Answer

This is just a different timezone format provided by the Zoneinfo database:

The time zones in the database are
given uniform names, such as
“America/New_York”, in an attempt to
make them easier to understand by
humans and to remove ambiguity.