Tiger is Mac OS X 10.4"
I was using OS X 10.3 (Panther) for quite a few years, finally I decided to upgrade the OS to 10.4 on my iBook G3. iBook G3 is a very old hardware, I should upgrade my hardware.
Most software doesn't support 10.3 any more, it stated for 10.4 or 10.5 (Leopard). The following are the list of software that I frequently use but not able to upgrade.
The number one on the list is Firefox browser. When Mozilla release version 3, I heard it improves in memory management, I would like to try the software, but the software refused to install because it need OS X 10.4 or above.
Safari browser on my OS X 10.3 is version 1.0, the latest version of Safari is 3, it needs 10.4 as well.
Picasaweb (Google's photo sharing site) has a uploader for iPhoto, but it needs a later version of iPhoto which available on OS X 10.4.
VLC is a very popular video player, version 0.8.6c is the last version which work on my OS X 10.3, even though it didn't stated that it needs 10.4. VLC 0.8.6d (or above) just don't run on my iBook with OS X 10.3.
Limewire which is a Java application for p2p file sharing services, theoretically it should base on Java platform version and not the OS, surprisingly the latest version of LimeWire needs OS X 10.4. The old version 4.12 still runs on 10.3.
I can still using the old version for some of the applications on OS X 10.3, which still working fine. Upgrade to 10.4 allow me to try more software. New release software like MySQL, php and a few others only package for 10.4 (or above).
One day OS X software may only runs on latest version of OS X and intel (x86) platform, like Joost TV and Divx codec for quicktime. When the day comes, hardware upgrade will be the only way.