During the time the netbooks were around, there was a Netbook Remix edition of Ubuntu that used the Unity UI which was eventually brought over to all editions of Ubuntu with Netbook Remix edition being made obsolete. It was a controversial move at the time as if the UI layout and design were different while still bringing in some shiny looking icons until Unity 8 is where all the glassy-ness is gone with solid looking rounded squares. The icons in Unity for Ubuntu may probably look like the Superbar from Windows 7 although the others may compare the Unity UI to the Mac Dock UI. The similarity is that you click on the icons to open their corresponding programs and if you close those programs, the icons in the Unity bar are still intact. However, if you open a different program whose icon is not in the Unity bar, it’s a similar vein to opening a different program in Windows 7 and Mac OSX. Certain programs in Mac Dock have their special menus where else in Windows 7 and Unity for Ubuntu, certain programs have special commands on the menu when you right-click on them on the taskbar.
In the near future starting next year, Ubuntu will be switching back to using GNOME although it uses GNOME 3 whose UI is different than the classic GNOME so if you click on the top left in GNOME 3 and Unity, you get to see many apps on the screen and somehow, GNOME 3 has the similar elements to Unity UI. So, the controversy isn’t over yet when switching back to GNOME like that with GNOME 3 in the future. The workaround is to install the classic GNOME like I already did with Ubuntu on my computer the last time although the UI layout was restored that way, it wasn’t the same from the way it looks in current Ubuntu OSes like everything is going all solid with lack of gradients.
The situation is that Canonical is moving towards cloud computing, Internet of Things along with Ubuntu Core and Snap apps which are applicable to IoT devices. Of course, running their own data center for the sake of cloud computing is energy and money consuming but what will they get is the money from the users running virtual machines in the cloud as part of the monthly subscription. This obviously makes more business sense that way as having to turn a phone into a computer will still give you limited software resources that is if you’re running Windows 10. On Ubuntu Touch for phones and tablets, you’re still sort of limited in the same vein as Windows 10 Mobile but from their demonstration, you should be able to run desktop-like apps stored on those devices when using Convergence.
Needless to say, both Unity and newer versions of GNOME are likely to take up more resources than the classic version. You could have run the other editions of Ubuntu if that’s the case on the old computers.