Difference between ctags and exuberant ctags

From raju

Q. What is the difference between ctags and exuberant ctags?
A.

rajulocal@hogwarts ~ % apt-cache search --names-only ctags
exuberant-ctags - build tag file indexes of source code definitions
libparse-exuberantctags-perl - exuberant ctags parser for Perl
rajulocal@hogwarts ~ % rmadison exuberant-ctags           
debian:
 exuberant-ctags | 1:5.8-3squeeze1            | squeeze         | source, amd64, armel, i386, ia64, kfreebsd-amd64, kfreebsd-i386, mips, mipsel, powerpc, s390, sparc
 exuberant-ctags | 1:5.8-3squeeze2            | squeeze-lts     | source, amd64, i386
 exuberant-ctags | 1:5.9~svn20110310-4+deb7u1 | wheezy-security | source, amd64, armel, armhf, i386, ia64, kfreebsd-amd64, kfreebsd-i386, mips, mipsel, powerpc, s390, s390x, sparc
 exuberant-ctags | 1:5.9~svn20110310-4+deb7u1 | wheezy          | source, amd64, armel, armhf, i386, ia64, kfreebsd-amd64, kfreebsd-i386, mips, mipsel, powerpc, s390, s390x, sparc
 exuberant-ctags | 1:5.9~svn20110310-8        | jessie          | source, amd64, arm64, armel, armhf, i386, kfreebsd-amd64, kfreebsd-i386, mips, mipsel, powerpc, ppc64el, s390x
 exuberant-ctags | 1:5.9~svn20110310-8        | sid             | source, amd64, arm64, armel, armhf, hurd-i386, i386, kfreebsd-amd64, kfreebsd-i386, mips, mipsel, powerpc, ppc64el, s390x, sparc
new:
$ ctags --version