Solid.
An author filter would be great.

It is the honestly the best extension! But please add a feature to customize the timing when a new quote is shown. For example, if someone only wants to see one quote per day no matter how many tabs they open, or you can add a timer which controls the refreshing time of the text. Else great work!

Simple and elegant

Simple, smooth, works without any hassle.
Reminds me to stay serene.