You will need to install a user script manager extension to install this script.
This is a script originally by aaferrari at userscripts.org.
Disqus broke it, so I asked for help here. The very nice wOxxOm located and fixed the errors.
Here is the working script. Original description follows:
"Tired of Disqus never remember your preferred way of sort comments or that these do not automatically load all?. Well if so, this script is what you were looking for.
Automates the following processes:
Sort comments by newest, the oldest or the best.
Load all comments when they are over 50 (or the maximum number of comments allowed per page).
Unhide those comments containing a link such as “see more”.
Check the option “I prefer commenting as guest” when you click in the textbox to write the nick.
All these actions can be configured by accessing at the settings panel (currently in English and Spanish) found in Tools > Greasemonkey > User Script Commands... > [Disqus Click Automate] Configuration. "
Many kind thanks to aaferrari and wOxxOm.
0.5 - Loosened timers a bit for Disqus lag. Also now cleans mangled links posted in comments so that they don't point to Disqus anymore...
0.6 - Fixed missing semicolon on line 46, thanks Jameson Quinn!
0.7 - Added a timeout to a place it was getting hung up on due to a Disqus change. Getting very kludgy, still mostly works, but badly needs a complete rewrite.