OnWorks Lubuntu online is a variant of Ubuntu that uses the LXQt desktop environment. It includes essential applications and services for daily use, including office suite, PDF reader, image editor and multimedia players. Lubuntu online is intended to be user-friendly, lightweight and energy efficient.
As you can see in this OnWorks platform the objective of the Lubuntu online is to create a variant of Ubuntu that is lighter, less resource hungry and more energy-efficient by using lightweight applications and LXDE, The Lightweight X11 Desktop Environment, as its default GUI.
As a result of that Lubuntu is targeted at PC and laptop users running on low-spec hardware that, in most cases, just don't have enough resources for all the bells and whistles of the "full-featured" mainstream distributions. Members of the team take care of LXDE and other packages that are part of this Lubuntu online.
Lubuntu received official recognition as a formal member of the Ubuntu family, commencing with Lubuntu 11.10. Even though Lubuntu is a lightweight distribution, it does not mean you will not be able to run all applications that other distributions are currently offering. It does mean that it is prepared and developed for low-specification computers.
Nonetheless, you can run any application available in the official repositories, as long as your hardware can bear with it.