Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Unity Linux had their first release on 09/07/2010 after around 1.5 years of development. The project was created in 2009 after some developers in the PClinuxOS (hereafter abbreviated PCLOS) community were unhappy about being shut out, as they perceived it, after the project leader Texstar had returned. One of them was KDulcimer who at the time had his own project TinyMe based on PCLOS, which according to the website started in 2006. He announced to continue his distribution but in the future base it on Mandriva, which PCLOS 2007 was based on as well.
TinyMe was and is intended to be a minimalist and light weight distribution and live CD for older computers with less resources or as a base to build up the ideal distribution for your own use. Just add software, desktop environments etc. TinyMe is built around the Openbox window manager and LXpanel. This is very similar to the LXDE desktop of today, but it did not officially have a release then.
Unity Linux is in many ways very similar. It also is "a minimalist distribution and live CD based on Mandriva Linux." It also strives to "create a base operating system from which more complete, user-oriented distribution can easily be built - either by other distribution projects or by the users themselves." Unity Linux also uses Openbox and LXpanel as the default environment. Package management "is handled via Smart and RPM 5 which can download and install additional software packages from the project's online repository." If I understand correctly, TinyMe is now based on Unity Linux.