Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
One of the defining characteristics of Linux is its open nature. As one of the most popular modern distributions, Ubuntu has seen its share of modifications, respins, and derivatives. One of the latest Ubuntu offspring is Lubuntu, which mixes the basic distribution with the LXDE desktop environment and Openbox window manager.
The developers' goal is to produce a truly “lightweight” distribution which can run on even older or lower-specification hardware than the basic Ubuntu. This niche is also targeted to some extent by Xubuntu, which grafts XFCE onto Ubuntu, but whose “lightweight” credentials have been questioned as it has evolved. I used Lubuntu as a primary working distribution on my Acer AS1410 subnote for around three months, and found it to be a solid and reliable distribution with a simple and user-friendly desktop that's an excellent choice for the right users.
Lubuntu weighs in towards the bottom of the Ubuntu family in download size at 521MB, suitable for burning to a single CD or a reasonably inexpensive flash drive. I ran Lubuntu both from a persistent USB drive and from a 5400 rpm internal hard drive, and found the main difference to be the much faster boot speed of the hard drive boot. Regardless of where I ran the distribution from, however, it it was snappy and responsive.