Ubuntu is one of the most used Linux operating system in the world.Their OS works on the system with RAM as low as 256 mb ,which is a boon for all those who uses old computers and don’t want to upgrade to new machines for the love sake.
But that may end very soon as the support for the 8.04 server,10.04 desktop and 11.10 will end on 9th May 2013. So the phased out OS will not receive support after 9th May. So many who were happy with old machines may have to go for the new one or has to add extra RAM for new OS.
But those are minor issue considering the security issues and vulnerabilities Ubuntu has to fix for every version. The end provides better support for the existing OSes.
Canonical has advised to upgrade to Ubuntu 12.04 to get the support for the latest security updates.