From LXF Wiki
For many years, ext2 was the default filesystem on Linux, offering an excellent blend of stability and performance. However, it lacked journaling, and when other filesystems such as ReiserFS and JFS came onto the scene, ext2's developers added journaling support in the form of ext3. (This prevented massive filesystem corruption in the event of a crash or power outage.) Today, many distros offer ext2/3 formatting options in their installers, although some default to ReiserFS.