Rated 5 out of 5 stars
Every now and then you find something that improves how you work. Having the ability to view two pages side by side, or even several tabs tiled together has significantly changed how I work on the Web.
Referencing documentation, viewing a video, commenting on a blog, can all now happen simultaneously--at least if you're brains up to it and you've had enough coffee. :)
If you find yourself resizing windows so you can see them both at the same time, then this is the add-on for you.