Does gnome support desktop widgets?

You can actually install and run plasma from Gnome if you so desire. It should work, despite having a lot of KDE dependencies, just add it to the startup programs. I am testing this right now, if you would like this option, I will report back to you.

There are also a few programs in the software center that allow you to use desktop applets. Search for gdesklets and screenlets. Here are articles:

http://en.wikipedia.org/wiki/Screenlets

http://en.wikipedia.org/wiki/Gdesklets

Linux is quite modular. :)

Screenlets and gDesklets are no longer maintained so I created flidget, a flexible, lightweight and concise widget system:

https://github.com/mrubioroy/flidget

I like Screenlets (from standard repos) . Much better then gDesklets for me.

If you want use KDE Plasma Widget (Plasmoid) maybe you can look my answer in this Question Run Plasma Widget in Gnome :)