Software Screenshot:
Find On Reddit searches for entries of the url of the tab you are on on reddit so you can quickly find comments on it. Lets say you followed a link through on reddit, and already closed the comments window. To find your way back to the comments window you would have to go back to the main page and wade your way through all the submissions until you found the submission again, OR you can just push this button.
Requirements:
Google Chrome
Comments not found