Currently I have gwibber 3.1.0~bzr997-0ubuntu1~daily1~maverick installed, and attached is a screenshot comparing the enabled vs. disabled state of the Twitter icon.
As you'll see in the screenshot the disabled state results only in the icon's opacity being reduced. I would suggest a more obvious effect such as a complete desaturation of the icon's colour in combination with removing the blue background/border of the icon.
Currently I have gwibber 3.1.0~bzr997- 0ubuntu1~ daily1~ maverick installed, and attached is a screenshot comparing the enabled vs. disabled state of the Twitter icon.
As you'll see in the screenshot the disabled state results only in the icon's opacity being reduced. I would suggest a more obvious effect such as a complete desaturation of the icon's colour in combination with removing the blue background/border of the icon.